Motion control of bionic inchworm robot based on MPC

DU Qiaoling; XUE Chengze; ZHENG Wei

doi:10.7688/j.issn.1000-1646.2025.01.16

Abstract：[Objective]With the rapid advancement of technology,our living environment is undergoing tremendous changes.The agglomeration of industrialization and the increase in population density have prompted buildings to continuously rise or extend downward,resulting in many places that are inconvenient or impossible for people to reach,but robots are accessible to them.One of the most popular research directions for robots currently is the development of robots with unconventional structures.By streamlining their redundant structures and reducing their size,while adding corresponding functional structures,robots can replace people in performing tasks in places where it is not suitable for humans to work.[Methods]This paper developed a climbing inchworm-inspired robot.To optimize the gait of the inchworm robot during motion,the paper proposeed a motion control method for the inchworm robot with bionic suckers based on model predictive control(MPC).An octopus-inspired negative-pressure sucker was designed according to the sucker structure of octopuses,and a sucker control model was established.Closed-loop control was achieved using data fed back by a pressure sensor.Based on the MPC bionic sucker controller(MPC-BSC),the paper also proposed a motion gait for the inchworm robot under model predictive bionic sucker control.[Results]The results of robot simulation experiments and tests show that the MPC-BSC has obvious advantages over PID control in terms of sucker pressure optimization.The inchworm robot based on MPC-BSC can complete an Ω-shaped motion gait in both horizontal and vertical tile planes.The main research contents of this paper are as follows:An octopus-inspired negative-pressure sucker was designed,and a sucker control model was proposed.Under negative pressure control,the suction pressure of the sucker can be adjusted to meet the adsorption force requirements for body structure movement.A bionic sucker control algorithm based on MPC was proposed.This algorithm adjusts suction force of the sucker by regulating the flow rate of the vacuum pump.A inchworm robot with bionic suckers was designed,with four longitudinal servo motors and two transverse servo motors installed on its body structure,which could achieve Ω-shaped motion gait and turning gait.Motion gait planning with MPC-BSC is proposed to achieve the Ω-shaped motion gait and turning gait.Experimental testing on the performance of the bionic sucker verifies the effect of edge structure on the adsorption force of the bionic sucker.[Conclusion]The feasibility of the bionic sucker control algorithm based on MPC is tested through simulation,and experiments verify that the inchworm robot can achieve Ω-shaped motion gait and turning gait on planes with different inclinations and materials.The bionic sucker structure developed in this paper expands the application scenarios for the adsorption function of robots and reduces the complexity of this function.The Ω-shaped motion gait proposed in this paper provides valuable reference for the movement of robots with unconventional structures,enabling them to move simply and efficiently in complex terrains.