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For equine-assisted therapy, a bionic horse configuration is presented. A bionic horse's single leg system has two degrees of freedom (DOFs), which is driven by a cam-linkage mechanism and can adjust the leg's endpoint trajectory. Based on analyzing the motion law of the bionic horse and the foot trajectory's requirements of the leg system, a multi-objective optimization model is established based on the foot trajectory performance index. To determine the objective function, the errors between the ideal foot trajectory and the mechanism motion model's foot trajectory, and the errors between the actual adjustable values and the target values for the motion range are taken as the optimization objective. In terms of the constraint conditions, the structural constraints, kinematic feasible region conditions, pressure angle requirements, et al., are considered. The ideal mechanism parameters are obtained by the intelligent optimization method. The results are verified by simulation modeling and experimental prototype, and the relevant ideas can provide a reference for the research of similar problems. [ABSTRACT FROM AUTHOR]

The cam-linkage mechanism is a typical transmission mechanism in mechanical science and is widely used in various automated production equipment. However, conventional modeling methods mainly focus on the design and dimensional synthesis of the cam-linkage mechanism in the slow-speed scenario. The influence of component dimensions is not taken into consideration. As a result, the model accuracy dramatically falls when analyzing large-size cam-linkage mechanisms, especially in high-speed environments. The kinematic aspects of cam design have been investigated, but there are few studies discussing the motion characteristic and accuracy analysis models of the large-size cam-linkage mechanism under high-speed scenarios. To handle such issues, this paper proposes a parameter optimization methodology for the design analysis of the large-size high-speed cam-linkage mechanism considering kinematic performance. Firstly, the mathematical model of the cam five-bar mechanism is presented. The cam curve and motion parameters are solved forward with linkage length and output speed. Then, a particle swarm-based multi-objective optimization method is developed to find the optimal structure parameters and output speed curve to minimize cam pressure angle and roller acceleration and maximize linkage mechanism drive angle. A Monte Carlo-based framework is put forward for the reliability and sensitivity analysis of kinematic accuracy. Finally, a transverse device of a sanitary product production line is provided to demonstrate the applicability of the proposed method. With the parameter optimization, the productivity of the transverse device is doubled, from 600 pieces per minute (PPM) to 1200 PPM. [ABSTRACT FROM AUTHOR]

Exact 3D path generation is a fundamental problem of designing a mechanism to make a point exactly move along a prescribed 3D path, driven by a single actuator. Existing mechanisms are insufficient to address this problem. Planar linkages and their combinations with gears and/or plate cams can only generate 2D paths while 1-DOF spatial linkages can only generate 3D paths with rather simple shapes. In this paper, we present a new 3D cam-linkage mechanism, consisting of two 3D cams and five links, for exactly generating a continuous 3D path. To design a 3D cam-linkage mechanism, we first model a 3-DOF 5-bar spatial linkage to exactly generate a prescribed 3D path and then reduce the spatial linkage's DOFs from 3 to 1 by composing the linkage with two 3D cam-follower mechanisms. Our computational approach optimizes the 3D cam-linkage mechanism's topology and geometry to minimize the mechanism's total weight while ensuring smooth, collision-free, and singularity-free motion. We show that our 3D cam-linkage mechanism is able to exactly generate a continuous 3D path with arbitrary shape and a finite number of C0 points, evaluate the mechanism's kinematic performance with 3D printed prototypes, and demonstrate that the mechanism can be generalized for exact 3D motion generation. [ABSTRACT FROM AUTHOR]

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In this paper, a cam-linkage mechanism with a swing follower with variable pivot has been studied. In this mechanism, the pivot of the swing follower is installed on a slider with an adjustable track direction, the follower performs a complex planar motion, and the motion range of the output angle can be adjusted according to the output requirements. In order to synthesize this mechanism, firstly, the relevant model is established and the basic structural parameters are optimized by considering the assembly conditions and the pressure angle under the limit position of the movement track of the follower mounting slider. Subsequently, the inverse method and the envelope theory are employed to derive the cam contour coordinates. Finally, the corresponding follower motion law is selected, the corresponding cam contour coordinates are calculated, and the entire cam contour curve is obtained using spline interpolation. An automatic design system for cam contours is developed. The processes are carried out through design examples and verified through motion simulations and prototype experiment. The present work can enrich the design theory of cam-linkage mechanisms. [ABSTRACT FROM AUTHOR]