Robot Motion Path Planning Under Joint Torque Limits
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Solution Overview
Problem
Current robotic motion planning methods do not adequately consider the mass and inertia of objects being lifted, leading to excessive strain and potential damage to robotic joints.
Innovation Solution
A computer-implemented method that adjusts robotic motion paths to account for mass and torque limitations by using input data such as robot kinematics, mass data, end effector kinematics, and drive configuration data, applying a motion path searching algorithm to identify feasible paths that comply with speed and torque limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If motion paths are planned based on minimal movement at high speed, then productivity is improved, but the torque on joints exceeds limits causing wear or breakage
Solution Approach 1:
The system dynamically adjusts motion parameters (speed, acceleration, trajectory) based on real-time torque calculations. The motion planner modifies path parameters to ensure torque remains within joint limits while maintaining efficient motion, directly resolving the contradiction between high-speed operation and joint durability
Solution Approach 2:
The system implements closed-loop feedback by continuously monitoring joint torque during motion execution and comparing it against predefined torque limits. When torque approaches limits, the system automatically adjusts motion parameters to prevent overload, ensuring joint durability while optimizing productivity
2Reliability
If the user manually redesigns motion paths using CAD tools, then joint strain is reduced, but the complexity of operation increases and time is lost
Solution Approach 1:
The motion planning system performs self-optimization by automatically calculating torque-compliant paths without user intervention. The system uses built-in torque models and joint limit data to generate safe motion paths autonomously, eliminating the need for manual CAD-based redesign while ensuring joint safety
Solution Approach 2:
The system replaces manual mechanical design processes with automated computational algorithms. Instead of users manually calculating torques using CAD tools, the system uses real-time computational mechanics and optimization algorithms to generate torque-compliant motion paths, reducing operational complexity
3Force
If stronger motors are installed to handle heavy loads, then the device can accomplish the task, but the cost increases and reprogramming is required
Solution Approach 1:
The system dynamically adapts motion parameters based on actual load conditions and joint torque limits rather than relying on oversized motors. By adjusting speed, acceleration, and trajectory in real-time, the system enables existing motors to handle heavy loads within their torque limits, avoiding the need for stronger motors and associated reprogramming
Data Source
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AI summary
According to other embodiments, a method planning of motions to lift heavy objects using a robot system comprising a robot and an end effector, includes identifying data comprising (a) rigid bodies included in the robot and the end effector, (b) joints connecting the rigid bodies, and (c) torque limits for each of the joints. The torque limit for a joint indicates a maximum supported torque by a drive operating the joint. A motion path searching algorithm is applied to the input data to identify feasible robot paths. The motion path searching algorithm determines torque of each of joint when evaluating points for inclusion in a feasible robot path. An evaluated point is only included in a feasible robot path if the torque of each of the joints do not exceed the torque limits. At least one of the feasible robot paths is transferred to a controller associated with the robot.