A New Metamorphic Parallel Leg Mechanism with Reconfigurable Moving Platform

This paper proposes the concept of full configuration state of metamorphic mechanism. Based on the concept, the configuration synthesis principle of metamorphic parallel mechanism is put forward. Firstly, a metamorphic parallel mechanism in full configuration state is synthesized, and then full configuration state evolves into a specific configuration state by increasing constraints or decreasing degrees of freedom. A reconfigurable moving platform based on the triple symmetric Bricard spatial closed-loop mechanism with a single degree of freedom is proposed. Based on this, a new method for switching motion configuration states of the metamorphic parallel mechanism is constructed. According to the configuration synthesis principle presented above, a novel metamorphic parallel mechanism that can switch between three- and four-degree-of-freedom is synthesized, and then the triple symmetric Bricard spatial closed-loop mechanism is used as the reconfigurable moving platform (that is, the reconfigurable foot of a walking robot) of the metamorphic mechanism, and thus, a novel metamorphic parallel leg mechanism is created. The screw theory is used to verify the degrees of freedom of the new type of metamorphic parallel leg. The proposed metamorphic parallel leg mechanism is expected to improve flexibility and adaptability of walking robots in unstructured environment.

Design of a New Waist for a Hexapod Robot With Parallel Leg Mechanism to Increase its Stair-Climbing Capability

A hexapod robot with parallel leg mechanism has been developed for rescue missions in nuclear power plants. The 1-UP & 2-UPS parallel leg mechanism has high payload but limited workspace which prevents the robot from climbing steep stairs. In this paper, a simple graphic method is proposed to estimate the robot’s stair-climbing capability based on its legs’ workspaces. The influence of the robot’s pitch motion on its payload capability is analyzed. Then a new waist mechanism which consists of a dual-parallelogram architecture is designed for the robot to increase its stair-climbing capability. Finally a simulation is carried out to demonstrate the robot’s stair-climbing capability with the help of the waist mechanism, and a prototype has been built and tested.

Kinematic Performance Analysis for Hexapod Mobile Robot Using Parallel Mechanism

Walking robots have been studied a lot over last several decades due to their good adaptability in different complex environments. The walking robot in this paper is designed for the research on emergency rescue missions in nuclear plants. Unlike other mobile robots, it apply parallel mechanism for its legs. This paper mainly focus on the kinematic performance of the parallel leg mechanism. Section 2 gives a brief introduction of our robot and the kinematic model. Then section 3 analyze the workspace of the leg tip. After that the payload and velocity capability are discussed respectively and it turns out that the mechanism has very good payload performance but the velocity is relatively low. Next the isotropic characteristic is studied in the whole workspace. Then the experiments indicate that the robot can successfully finish walking and manipulating tasks.

Design and Analysis of the Quadruped Walking Robot Based on 3-RPS Parallel Mechanism

Based on the importance of the robot for the elderly and the disabled, a quadruped walking robot using 3-RPS parallel mechanism as the basic leg mechanism is proposed. The structure of the basic leg is described, and the whole structure of the quadruped walking robot is formed. Then taking the workspace of the basic leg as the standard, the optimum size parameters of the upper platform and the lower platform of the based leg are achieved. Meanwhile the workspace of the basic leg is obtained by the anti-solution search method. Taking the basic leg as analysis object and applying the virtual organization method, the kinematic expression is got. All of these analyses lay a theoretical foundation for the further study on the quadruped walking robot with parallel leg mechanism.