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Modeling and simulation of a mechanism for suppressing the flipping problem of a jumping robot

Qi Li, Liang Peng, Zhiyuan Wu, Pengda Ye, Weitao Zhang, Yi Xu, Qing Shi

TL;DR

The paper tackles flipping instability in miniature jumping robots and proposes an Elastic Passive Joint (EPJ) that passively modulates body–leg interaction during flight. It combines dynamic modeling of takeoff and the aerial phase with MATLAB/Simulink simulations to compare EPJ-enabled and EPJ-disabled cases, showing that EPJ substantially reduces the body’s final angular velocity and enables flip-free jumps with optimized parameters. A parameter study identifies the revolute joint position and spring stiffness as key levers, with an optimal stiffness around $k \approx 1566\,\mathrm{N/m}$ achieving flip-free performance. The work demonstrates a lightweight mechanism to stabilize jumping mobility in micro-robots and informs future designs where center-of-mass sensitivity is a constraint.

Abstract

In order to solve the problem of stable jumping of micro robot, we design a special mechanism: elastic passive joint (EPJ). EPJ can assist in achieving smooth jumping through the opening-closing process when the robot jumps. First, we introduce the composition and operation principle of EPJ, and perform a dynamic modeling of the robot's jumping process. Then, in order to verify the effectiveness of EPJ in controlling the robot's smooth jump, we design a simulation experiment based on MATLAB. Through comparative experiments, it was proved that EPJ can greatly adjust the angular velocity of the robot and increase the jump distance of the robot. Finally, we analyze each parameter in EPJ and performs parameter optimization. After optimization, EPJ achieves a completely flip-free jump of the robot, laying an important foundation for improving the mobility of micro-robot.

Modeling and simulation of a mechanism for suppressing the flipping problem of a jumping robot

TL;DR

The paper tackles flipping instability in miniature jumping robots and proposes an Elastic Passive Joint (EPJ) that passively modulates body–leg interaction during flight. It combines dynamic modeling of takeoff and the aerial phase with MATLAB/Simulink simulations to compare EPJ-enabled and EPJ-disabled cases, showing that EPJ substantially reduces the body’s final angular velocity and enables flip-free jumps with optimized parameters. A parameter study identifies the revolute joint position and spring stiffness as key levers, with an optimal stiffness around achieving flip-free performance. The work demonstrates a lightweight mechanism to stabilize jumping mobility in micro-robots and informs future designs where center-of-mass sensitivity is a constraint.

Abstract

In order to solve the problem of stable jumping of micro robot, we design a special mechanism: elastic passive joint (EPJ). EPJ can assist in achieving smooth jumping through the opening-closing process when the robot jumps. First, we introduce the composition and operation principle of EPJ, and perform a dynamic modeling of the robot's jumping process. Then, in order to verify the effectiveness of EPJ in controlling the robot's smooth jump, we design a simulation experiment based on MATLAB. Through comparative experiments, it was proved that EPJ can greatly adjust the angular velocity of the robot and increase the jump distance of the robot. Finally, we analyze each parameter in EPJ and performs parameter optimization. After optimization, EPJ achieves a completely flip-free jump of the robot, laying an important foundation for improving the mobility of micro-robot.
Paper Structure (8 sections, 6 equations, 5 figures)

This paper contains 8 sections, 6 equations, 5 figures.

Table of Contents

  1. INTRODUCTION
  2. DESIGN AND MODELING OF THE MECHANISM
  3. Mechanism Design
  4. Modeling of The Jumping Process
  5. SIMULATION ANALYSIS
  6. Comparative analysis with or without EPJ
  7. Optimization analysis of the parameter of EPJ
  8. CONCLUSIONS

Figures (5)

  • Figure 1: Jumping robot mechanism design: (a)The rendering of the robot as a whole; (b)The longitudinal cataway view of EPJ; (c)The leg squeezes the switch to rotate it, releasing EPJ; (d)The leg gradually rotates to away from the body.
  • Figure 2: Simplified Model of Mechanical Structure: (a)EPJ is not triggered and the leg is simplified into a two-link mechanism; (b)EPJ works, generating a rotation angle between the body and the leg.
  • Figure 3: The jumping orientation of a robot: (a)Robot with EPJ, the robot is simplified to a four-bar linkage; (b)The motion trajectories of each joint with EPJ. At the moment of take-off, the body's angular velocity is -0.02 rad/s, and the leg's angular velocity is 29.99 rad/s; (c)Changes in the robot's angular velocity during the aerial phase; (d)Robot without EPJ. The mechanism is simplified to a three-bar linkage; (e)The motion trajectory without EPJ; (f)After taking-off, the angular velocity is -3.46 rad/s.
  • Figure 4: The relation between the position of the revolute joint and the angular velocity.(a)The angular velocity changes with x coordinate.(b)The angular velocity changes with y coordinate.
  • Figure 5: The results of EPJ parameter optimization.(a)The final angular velocity of the robot varies with the stiffness coefficient of the spring.(b)The jumping height of the robot varies with the stiffness coefficient of the spring.(c)The jumping distance of the robot varies with the stiffness coefficient of the spring.