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In order to ensure humanoid robot can cross obstacle autonomously in unstructured environment, a gait planning method is proposed for humanoid robot to step over 2D discrete terrain. According to the target step location and considering the geometric constraints, speed constraints, dynamic performance constraints and stability constraints of the robot in the real world, a differential evolution algorithm is used to search the feasible trajectories of the hip and ankle joints. In order to realize real time gait planning, robot joint trajectories for different target step locations is optimized offline and a gait library is established. By using Webots simulator in conjunction with MATLAB, the robot can send the data of obstacle detected by LiDAR in Webots to MATLAB to calculate corresponding step location and call joint trajectories in gait library automatically. The results show that the proposed method can realize stable walking of humanoid robot to step over stochastic discrete terrain.

This paper innovatively proposes a new multi-objective optimization method applied in robust walking with preset step-length of biped, using modified JAYA algorithm. The biped is structured with eleven links activated by ten joints. The hip and feet position and speed of biped are determined based on the inverse kinematics. Two objectives related to the stability of biped in walking and to follow the preset step-length value have been satisfactorily investigated, and Pareto optimum front of resolutions has been attained. As to demonstrate the effectiveness of proposed MO-JAYA, it takes comparative results with MO-PSO and MO-NSGA-2. The simulation and experimental results investigated on the real biped system HUBOT-5 confirm that the proposed MO-JAYA ensures an effective and robust gait planning for biped with accurate step-length magnitude.

At present, the forward-flapping gait of a hexapod robot has a large deviation from the direction of motion. This thesis compared and analyzed the force acting on the foot of the robot in forward-flapping and quadruped-propulsive gait, and the mechanism of the robot's deviation in straight-line walking is obtained by theoretical analysis; Then through theoretical analysis and experiment, the lateral force on the foot of forward-flapping gait is obtained. Finally, the experiment results show that the quadruped-propulsive gait can solve the problem of the deviation of robot well.

The characteristics of Hopf oscillator are analyzed, and the feasibility of its application in gait generation of quadruped robot is discussed. Two kinds of CPG control networks are constructed by using Hopf oscillator and the structures of the two networks are analyzed and modeled. These two CPG can produce stable gait with strict phase relationship. The robot simulation software Webots and MATLAB are used for co-simulation. According to the output control signal of CPG network, each joint of quadruped robot is controlled and trot gait planning is realized. The simulation results show that the CPG network constructed by Hopf oscillator can achieve good gait planning for quadruped robot, which has the advantages of simple model and clear thinking.

In order to meet requirements of diverse activities of exoskeleton robot in practical application, a dynamic motion planning system is proposed using a fast parameterized gait planning method in this article. This method can plan the required gait data by adaptively adjusting very few parameters according to different application requirements. The inverted pendulum model is used to ensure the sagittal stability of the robot in the planning process. And this article specifies the end location of robot and iterates the associated joint angles by inverse kinematics. The gait trajectories generated by the proposed method are applied to the lightweight lower-limb exoskeleton robot. The results demonstrate that the trajectories of gait can be online generated smoothly and correctly, meanwhile every variable step can be satisfied as expected.

Gait planning is essential for biped robots because the stability of the two support is very challenging task. A special attention is required to get a stabilized gait for humanoid robots. In this paper, 3D-LIPM (linear inverted pendulum model) is used to solve the gait planning problems of humanoid robots. Humanoid robot NAO is utilized as robotic platform. The structure of the robotic platform decides the period step height and step length. The gait planning consists of model of 3D-LIPM and ZMP (zero moment point). Simulation and experiments are carried out on simulated and real NAO, and showing good agreement with each other. An ideal controlled gait is obtained using the proposed technique.

Multilegged robots, especially Quadruped robots are gaining more importance due to their flexibility and adaptability to the environment. Mobility is one of the challenges in quadruped robots. Building a robot with smooth and stable locomotion will have wider applications in business and home. This paper focuses on the approach to be followed to implement gait planning to ensure smooth walking and stability for a quadruped robot with the use of artificial intelligence. A quadruped robot will be first created in simulation environment for training. Later we will develop a 4-legged quadruped robot having 12 degrees of freedom and implement improved gait planning for smooth locomotion and stability. Simulation and modelling of the robot will be carried out using simulation tools like Pybullet, Solidworks, etc.

Pushing ground with trailing leg to gain energy is the main way of energy input for biped robots. This paper studies the control method of ground-push in dynamic walking of biped robots. First, the principle of the ground-push is studied. Second, the implement method of ground-push, which is for a 27 DOF humanoid robot, and under a decentralized control architecture, is developed. At final, the proposed method is verified in the simulation. The results show that the proposed method achieves stable walking, and the performance of speed control is satisfied.

In order to allow quadruped robots to adapt to the complex working environment in the field of fisheries and aquaculture, a new type of quadruped robot with linear and rotary driving is proposed, and the kinematic inverse solution of the leg of the quadruped robot is deduced. For achieving quadruped robot smooth walking, the straight gait of the quadruped robot is planned according to the stability margin principle of motion, so that the stability margin of the machine is 20 mm when three legs supporting it. The planning gait is simulated by ADAMS software, the kinematics and dynamics analysis of the four main driving mechanisms of the robot leg were carried out, and the feasibility of using the STEP5 driving function to execute the planning gait in the quadruped robot was verified. The theoretical and simulation curve analysis results show that, the quadruped robot according to the planned gait can complete the cycle and have a stable walking. The results of this study can provide a reference for the practical application of the new amphibious quadruped robot in the fields of complex and uneven ground in the field of fisheries and aquaculture to realize exploration, fishing and transportation.

The humanoid robot has the characteristics of nonlinearity, multi-structure and unstable walking. When planning its gait, it should fully consider the walking environment and the gait parameters involved in each movement. In addition, the stability and energy efficiency of the robot should be satisfied as much as possible, and the relationship between the joint angles of the legs should be determined. In this paper, the gait stability controller is designed by using DQN algorithm, and the offline gait based on model generation is optimized online. Through MATLAB simulation experiment, it is proved that good control effect can be achieved and the stability during walking is effectively improved.

Mobility impairment is becoming a challenging issue around the world with a rapid increase on aging population. Existing tools of walking assistance for mobility-impaired people include passive canes or wheeled rollators which increase energy consumption on the users and disturb the users’ walking rhythm, and powered wheeled chairs which could preclude the muscle activities and accelerate the degeneration of the lower limbs. The research in this paper aiming at helping mobility-impaired people proposes a novel robotic platform with quadrupedal locomotion. With motorized actuation, the quadruped robotic platform could accompany the user at the center and provide protection and possible walking assistance if needed. As the robotic platform is equipped with a leg locomotion, it can enlarge the user’s activity environments, such as both indoor flat floor and outdoor uneven terrain. It can even assist the user to involve in some mobility challenging activities, such as climbing stairs. In this paper, we illustrate the mechanical design of the robotic platform. A continuous gait planning is proposed to create a smooth locomotion for the robot. To quantify the performance, a system-level walking experimentation was conducted, and the results showed that quadruped robotic platform can maintain a statically stability which demonstrate the feasibility and capability of the robotic application for walking assistance.

This paper presents a novel CPG-based gait generation of the curved-leg hexapod robot that can enable smooth gait transitions between multi-mode gaits. First, the locomotion of the curved leg and instability during the gait transitions are analyzed. Then, a modified Hopf oscillator is applied in the CPG control, which can realize multiple gaits by adjusting a simple parameter. In addition, a smooth gait switching method is also proposed via smooth gait transition functions and gait planning. Tripod gait, quadruped gait, and wave gait are planned for the hexapod robot to achieve quick and stable gait transitions smoothly and continuously. MATLAB and ADAMS simulations and corresponding practical experiments are conducted. The results show that the proposed method can achieve smooth and continuous mutual gait transitions, which proves the effectiveness of the proposed CPG-based hexapod robot control.

Climbing stairs is an important ability for humanoid robots. This paper proposes a target location and gait planning method for humanoid robot climbing stairs. Target location enables the humanoid robot to accurately locate the stair position, and the gait planning algorithm makes the humanoid robot to climb the stairs. In order to enable the humanoid robot to climb multiple stairs, this paper proposes control strategy of motion for humanoid robot. The effectiveness of our proposed method was confirmed by experiments. The experimental results show that this method improves the accuracy of target location, and enables the humanoid robot Nao to climb a staircase with 2.928 cm steps.

This paper presents a double generating functions method to generate energy-optimal trot gait for the quadruped robot. First the trot gait of the quadruped robot is reduced to the walking gait of the biped robot and the dynamic equation is derived, then a double generating functions based approach is introduced to generate its energy-optimal gait, at last the multi-step simulation is implemented to illustrate the effectiveness of the method. Since the approach moves a large amount of the common computational effort to the off-line part, it provides a fundamental efficiency in on-line energy-optimal gait planning over other conventional methods.

This paper presents the new version of gait planning algorithm for humanoid robot. Gait with variable step length was considered. The method delivers the joint trajectories for given trajectory of the Zero Moment Point. The Preview Control concept was used. Results were obtained in simulations and were verified on the hardware. The algorithm was tested on planar 6 Degrees of Freedom humanoid robot. Robot performed defined number of steps without loosing its balance.

In the last years the autonomy in service robots became an important feature to develop different kinds of indoor and outdoor service tasks, like sur-veillance or inspection in hospitals. This autonomy is not only related to power consumption, it is also related with the capability to avoid obstacles without crashing. The aim of this paper is to present the experimental validation of a gait planning for obstacle avoidance with Cassino Hexapod III, a wheeled-legged hy-brid hexapod robot, with an omni-wheeled locomotion. Experimental test is car-ried out to demonstrate the motion capability of Cassino Hexapod III to dodge an obstacle in front of it.

Quadruped robot has gained considerable interests since its wide applications in both military and entertainment scenarios. On the control and gait planning of quadruped robots, walking stability is the fundamental problem in most scenarios. In this paper, we proposed a gait phase optimization method on the swing foot of quadruped robots in walking gait. In the proposed gait optimization method, Lift-up and Touch-down phases are added in gait planning of swing foot, which aiming to improve the stability in walking phases. Finally we validate the proposed method on a quadruped robot, and experimental results indicate that the proposed gait phase optimization method has the ability to improve the stability of the quadruped robot in walking gait.

With the capability to enable lower limb paralysis people to stand up and walk again, lower limb exoskeleton has become more and more popular over the world. However, most of the exoskeleton use the pre-defined or pre-planned movement gait which lack of flexibility and adaptability, thus limit the use of exoskeleton in outdoor environments. In this paper, we present a gait planning method with dynamic movement primitives to enable the lower limb exoskeleton walk up stairs smoothly. This approach can adjust the exoskeleton gait trajectory online for walking up stairs by detecting the position of the stair edge at each step. Compared to the previous methods, our method gives the lower limb exoskeleton the following advantages: more natural gait, better dynamic effects and higher autonomy, which may broaden the use of lower limb exoskeleton. Experiment results validate the presented gait planning method.

In recent years, walking training has been widely developed due to the increasement of patients with lower extremity motor dysfunction caused by spinal cord injury and stroke. Robotic gait-orthosis is a complex system and gait planning algorithm is an important aspect of it. Gait-orthosis should have the characteristics of naturalness, comfort and safety. In view of the importance of gait safety, this paper proposes gait by a method called security redundancy gait pattern generator (SRGPG). The SRGPG gait algorithm insures the safety of gait from two aspects, namely, gait parameter calculation and gait planning. On one hand, the gait parameter calculation is based on bionics principle and users' physical condition. On the other hand, in the gait planning, the whole gait is divided into three sub stages and the motion of all joints is planned in each sub stage. The SRGPG are tested by the simulation and experiment with XKF-01 robotic gait-orthosis. By comparing SRGPG and CGA gait results, the similarity between SRGPG gait curve and normal people's walking trajectory is verified. Finally, the experimental results demonstrate that the lower limb rehabilitation gait algorithm based on SRGPG is feasible and safe.

In this article, an energy-efficient gait planning algorithm that utilizes both 3D body motion and an allowable zero moment point region (AZR) is presented for biped robots based on a five-mass inverted pendulum model. The product of the load torque and angular velocity of all joint motors is used as an energy index function (EIF) to evaluate the energy consumption during walking. The algorithm takes the coefficients of the finite-order Fourier series to represent the motion space of the robot body centroid, and the motion space is gridded by discretizing these coefficients. Based on the geometric structure of the leg joints, an inverse kinematics method for calculating grid intersection points is designed. Of the points that satisfy the AZR constraints, the point with the lowest EIF value in each network line is selected as the seed. In the neighborhood of the seed, the point with the minimum EIF value in the motion space is successively approximated by the gradient descent method, and the corresponding joint angle sequence is stored in the database. Given a distance to be traveled, our algorithm plans a complete walking trajectory, including two starting steps, multiple cyclic steps, and two stopping steps, while minimizing the energy consumption. According to the preset AZR, the joint angle sequences of the robot are read from the database, and these sequences are adjusted for each step according to the zero-moment-point feedback during walking. To determine the effectiveness of the proposed algorithm, both dynamic simulation and walking experiment in the real environment were carried out. The experimental results show that compared with algorithms based on the fixed body height or vertical body motion, our gait algorithm has a significant energy-saving effect.

In this paper, we design a hexapod climbing robot and propose a cross-plane transition gait algorithm to solve the problem that the general walking robot can't perform the work at high altitude and can't realize the autonomous transition between multiple planes. Firstly, we build a simulation control system based on MATLAB and V-REP for algorithm analysis and motion verification. Meanwhile, virtual connection technology is used to design virtual suction sensor to simulate the real adhesion mechanisms. Then, the single-plane walking gait algorithm is designed based on the SS-Shaped interpolation function, which effectively avoid the wear of the adhesion mechanisms. The transition algorithm based on workspace constraints is designed to greatly improve the adaptability of robots in complex environments. Finally, the simulation of rhythmic gait motion and ground-slope transitional motion verify the effectiveness of the gait planning method.

The adapotation of gaits pattern is a basic and important for the hexapod robot to move stably and efficiently, which depends on the servos of the robot’s legs, and also the body structure of the robot.This paper compares the tripod gait and the crab-inspired gait for a specific hexapod to move forward and move backward; turn left and turn right and integrates the two gaits to apply them under different conditions. The hexapod has three servos on each legs, thus the freedom level of each leg is three-degree. From the comparative experiment, this two gait patterns are suitable for different turning demands.

In order to realize smooth gait planning and stability control of a quadruped robot, a new controller algorithm based on CPG-ZMP (central pattern generator-zero moment point) is put forward in this paper. To generate smooth gait and shorten the adjusting time of the model oscillation system, a new CPG model controller and its gait switching strategy based on Wilson-Cowan model are presented in the paper. The control signals of knee-hip joints are obtained by the improved multi-DOF reduced order control theory. To realize stability control, the adaptive speed adjustment and gait switch are completed by the real-time computing of ZMP. Experiment results show that the quadruped robot’s gaits are efficiently generated and the gait switch is smooth in the CPG control algorithm. Meanwhile, the stability of robot’s movement is improved greatly with the CPG-ZMP algorithm. The algorithm in this paper has good practicability, which lays a foundation for the production of the robot prototype.

Locomotion of earthworm-like metameric robots results from shape changes of deformable segments. Morphologically, the segments could stretch, contract or bend by changing their states. Periodic shape changes are recognized as gaits of the robots. Robots could employ different gaits for different locomotion tasks. However, earthworm-like robots generally possess a number of independent segments and their hyper-redundant morphology (Chirikjian G S and Burdick J W 1995 IEEE Trans. Robot. Autom. 11 781-93) poses a challenge to gait planning for their locomotion. Hence, the goal of this paper is to establish a framework of in-plane gait planning for earthworm-like robots. To this end, a generic model of earthworm-like robots modelled in our prior work (Zhan X et al 2019 Int. J. Robot. Res. 38 1751-1774) is firstly reviewed and in-plane gaits of the robot are parameterized by adopting the principle of retrograde peristaltic wave (Quillin K J 1999 J. Exp. Biol. 202 661-674). Following this, gaits of earthworm-like robots could be uniquely determined by gait parameters, and gait planning of the robots is then reduced to optimizing the gait parameters. The framework mainly consists of a locomotion simulation module and a genetic algorithm module. In the locomotion simulation, the performance of each gait would be evaluated, and then gait parameters get evolved based on the fitness in the genetic algorithm module. To evaluate the fitness of each gait, two objective functions, i.e., the distance to goals and the number of locomotion steps the earthworm-like robot taken before reaching the goals, are to be minimized in the optimization. Besides, two stopping criteria are proposed to improve the efficiency of evaluation. The framework proposed in the paper could plan in-plane gaits of earthworm-like robots, in contrast, only rectilinear locomotion is considered in similar works. This greatly advances the state of art of earthworm-like robots.

Hexapod bionic robot plays an important role in battlefield reconnaissance and battlefield rescue. However, due to the complex battlefield situation, the robot’s legs are often damaged due to attacks, electromagnetic interference and other reasons, so it cannot work normally according to the original gait planning. In this paper, the damage situation of the hexapod bionic robot gait planning study, establish a foot injury cases six-legged robot model, USES the existing six-legged robot, combined with Matlab simulation model, build six-legged robot for foot injury under the condition of six-legged robot, simulation analysis is carried out under the different gait, planning out the suitable gait of robot movement. According to the analysis, the suitable gait under the condition of different injuries was obtained. This study can be used to improve the adaptability of hexapod robot in battlefield conditions and extend the working life of hexapod robot.

In this paper, the rectangular wheel legged hexapod robot is used as the experimental robot, the STM32 single-chip microcomputer is used as the main control core, the steering control board is used as the auxiliary board, the upper computer programming is used to write the action group of the hexapod robot, the command is sent to the single-chip microcomputer through the PS2 handle, the single-chip microcomputer controls the steering board to achieve the corresponding action group, and the Arduino control board is used to change the environment through the sensor in the later stage The control of action group can be realized by the detection. In addition, in order to solve the gait planning problem of hexapod robot and realize the optimal learning of robot’s free gait on specific terrain, based on the discretization of the robot’s single foot distance, integrating the time rhythm principle of CPG model and the space rule constraint mechanism of reflection model, a discrete gait model of Hexapod robot is constructed. Ant colony algorithm is used to study the gait path planning of the robot. MATLAB and C language technology are used to realize the simulation of the gait planning of the hexapod robot.

In order to improve the swimming performance of a paddle-propelled crablike robot, the sequence and parameters of swimming gait are planned according to the bionic swimming mechanism. Based on the bionic prototype of Portunus trituberculatus, the structure scheme of a leg–paddle hybrid driven robot is proposed with the functions of walking on land, crawling on seabed, and swimming underwater. By analyzing the underwater propulsion mechanism of single paddle and hydrodynamic performance of double paddles cooperatively propulsion, four direct swimming gaits are planned and the corresponding attitude changes are theoretically analyzed. Then, the numerical simulation and direct swimming experiments are carried out to verify the effectiveness of proposed gaits and correctness of force analysis. In alternate swimming gait of lift-based mode, the robot swims forward in a rolling attitude, with an advantage of the minimum water resistance and the optimum swimming velocity and efficiency. The influence of flapping frequency and relative phases of paddles on the swimming velocity shows the trend of raise first and then fall.