Robot Joint Trajectory Planning for Synchronous Real-Time PTP Motion
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Solution Overview
Problem
Existing trajectory planning methods for point-to-point motion in robot joint space require a large calculation amount and often result in longer planned trajectory times, failing to meet real-time control requirements and affecting the efficiency of industrial robots.
Innovation Solution
A method that performs trajectory planning in robot joint space based on preset constraints for physical quantities of motion parameters, using a generalized virtual axis to calculate and verify motion parameters like velocity, acceleration, and jerk, ensuring all axes can satisfy constraints and move synchronously, reducing calculation and optimizing motion time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each axis is planned separately based on its motion parameters to obtain motion time and then trajectory planning is performed based on the maximum time, then synchronous PTP motion is achieved, but the calculation amount becomes huge requiring multiple trajectory planning calculations
Solution Approach 1:
The patent merges the trajectory planning of multiple axes into a unified calculation framework. By establishing a relationship between axes based on their motion parameters and combining their trajectory planning into a single coordinated system, the method reduces the number of separate calculations from 2n (in prior art) to a much smaller number, while still ensuring all axes reach the target point simultaneously.
Solution Approach 2:
The patent creates a universal trajectory planning formula that can be applied to multiple axes simultaneously. The unified calculation method serves as a multi-functional solution that determines the motion parameters for all axes in one calculation process, rather than requiring separate planning for each axis as in traditional methods.
2Reliability
If multiple trajectory planning calculations are performed for robots with multiple axes, then synchronous motion is achieved, but the trajectory points cannot be generated in a control cycle during real-time planning
Solution Approach 1:
The patent combines the trajectory planning calculations for all axes into a unified computation that can be completed within a single control cycle. By merging the separate 2n calculations into a coordinated system with fewer calculations, the method enables real-time generation of trajectory points for all axes simultaneously, meeting the requirements of real-time control systems.
3Productivity
If trajectory planning is performed with little calculation to satisfy real-time control requirements, then real-time performance is achieved, but the motion trajectory may not be smooth and optimal
Solution Approach 1:
The patent's unified trajectory planning formula serves multiple functions simultaneously: it ensures smooth and optimal motion trajectories while being computationally efficient enough for real-time control. The multi-functional approach calculates motion parameters for all axes in a coordinated manner, producing smooth trajectories without requiring multiple separate calculations.
4Adaptability or versatility
If each axis uses different physical quantities of motion parameters, then each axis can move independently, but the minimum time required for each axis to move to target position is different making synchronous motion difficult
Solution Approach 1:
The patent applies local quality by allowing each axis to maintain its own motion parameters (velocity, acceleration, jerk) while establishing a mathematical relationship between them. The unified trajectory planning formula coordinates these different local characteristics to achieve global synchronous motion, where each axis moves independently according to its parameters but arrives at the target simultaneously.
Data Source
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AI summary
A robot joint space point-to-point movement trajectory planning method. Joint space trajectory planning is performed according to the displacement of a robot from a start point to a target point during PTP movement and a limitation condition of a preset movement parameter physical quantity of each axis in a robot control system. An n-dimensional space is constructed by taking each axis of the robot as a vector, wherein n≥2, and the movement parameter physical quantity of each axis of the robot is verified according to a vector relationship between the n axes of the robot, so that a trajectory planning curve of each axis of the robot satisfies the limitation condition of the preset movement parameter physical quantity. The method has a small amount of calculations and strong real-time performance, the movement curves are mild, the control time is optimal, and the algorithm execution effect is good. The method is suitable for industrial robot on-site applications.