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BACKGROUND: Trans-oesophageal echocardiography (TOE) has been widely utilized for cardiac disease diagnosis and interventional procedure guidance. However, the TOE operator is required to manually manipulate the probe, often for long periods of time and sometimes in an X-ray environment where there is exposure to ionizing radiation.METHODS: A novel robotic manipulation system for remote control of commercial TOE probes has been developed and tested. The system has four degrees of freedom (DOFs) and is characterized by a kinematic model. The accuracy of the model and the error propagation were analysed.RESULTS: The prototype system was shown to exhibit the required function in terms of the mechanical reliability and range of motion. The forward kinematic model can accurately predict the trajectory of the probe tip movement. The average point-to-point errors were 2.60 mm and 3.55°.CONCLUSIONS: Robotic assistance provided by the proposed system may improve the TOE operating environment. The proposed forward kinematic model can be further employed for automatic control.

Continuum manipulators are a rapidly emerging class of robots. However, due to the complexity of their mathematical models and modelling inaccuracies, the development of effective control systems is a particularly challenging task. This paper presents the first attempt on kinematic control of continuum manipulators using a fuzzymodel- based approach. A fuzzy controller is proposed for autonomous execution of end-effector trajectory tracking tasks for a continuum manipulator. Particularly, membership functions are employed to combine the linearized state-space models, to achieve, overall, a fuzzy model. The fuzzy model can help design the fuzzy controller; in our approach this process is supported by a thorough stability analysis. This control methodology enables a solution with low computational requirements to this motion control problem - there is no need to continuously update the Jacobian of the continuum manipulator. The superior performance of this controller is validated in MATLAB simulations and compared with those of classical controllers found in the literature. The experiments on a rapid-prototyped continuum manipulator further verify the feasibility and the advantages of this fuzzy controller in the presence of modelling discrepancies and hardware inaccuracies.

The rigid-link manipulators have been extensively employed in industrial setting nowadays. However, problem arises when such manipulators are assigned to work alongside human or employed in cluttered, complex, and tight environment. Hence, continuum manipulator, with its inherent compliant and flexibility, is preferable in this aspect. In this paper, we present our recent work presenting a real-time pose estimation and obstacle avoidance for continuum manipulator in dynamic environments. The approach is shown to work in a model of both single-segment and multi-segment continuum manipulator and also in a real tendon-driven single-segment continuum manipulator in dynamic environment, and thus, suitable to be used in human environments.

In this paper, a potential-field-based real-time path planning algorithm for a multi-segment continuum manipulator is proposed. This planner is employed to enable a continuum-style manipulator to move autonomously in dynamic environments in real-time. The classic potential field method is modified to make it applicable for a kinematics model based on the constant-curvature assumption. The contribution of this paper lies in the design of a novel potential field in the actuator space satisfying the mechanical constraints of the manipulator. The planning algorithm is tested and validated in real-time simulation for a 3 segments continuum manipulator. Preliminary tests for a tendon-driven single-segment continuum manipulator prototype confirm the performance of the proposed planner.

There is a surge of research interest in the field of “continuum robotics.” Robots created under this paradigm offer many advantages and represent unique features in terms of flexibility, dexterity, safety, and weight reduction. This paper introduces a novel continuum manipulator that integrates multiple layers of compliant planar springs—a structure that provides several notable advantages over existing designs. First, it possesses precise linear large-displacement motion. In this context, we utilize the linear output motion of each layer of springs. With the serial connection of multiple conjoined layers, the manipulator demonstrates linear predictable bending even when executing large bends. An analytical method is provided to study the compliance characteristics of the planar spring and derive the compliance matrix to represent the force–deflection relationships, allowing an accurate motion prediction. Second, compared with work elsewhere, this structure demonstrates an effective way of decoupling bending from contraction and expansion. It reduces the uncontrolled compression when generating normal deflections, thus controlling robot bending is simplified. Third, the reachable workspace of the end effector is enlarged by means of varying the length of the continuum manipulator via controlled contraction and expansion. A 3-D printed prototype of this continuum manipulator is experimentally evaluated. The conducted experiments demonstrated validity of our approach.

Nowadays, rigid-link manipulators have been extensively used in various industrial applications, such as automotive industry and manufacturing operations. Nonetheless, despite of their precise and well-established position control, rigid-link manipulators suffer from their lack of flexibility, especially when operated in cluttered, unknown, dynamic environments, as well as their inherent rigidity which limits their applications in a shared human-robot workspace. In this paper, we report our current progress on mobile continuum manipulators application in dynamic environments. The results show that a continuum arm, mounted on a mobile platform and equipped with a reactive motion planner, is a promising candidate to be used in dynamic industrial environments.