Phase Synchronized Trajectory Generation for Robot Actuators
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Solution Overview
Problem
Existing robot trajectory generation techniques often fail to produce phase synchronized trajectories, which are essential for one-dimensional straight-line motion in multi-dimensional spaces, especially when time-optimal trajectories cannot be phase synchronized without violating kinematic motion constraints.
Innovation Solution
The method involves generating time-optimal trajectories for each actuator and, if phase synchronization is not achievable, time-scaling and phase-scaling these trajectories to create phase synchronized trajectories that may be less time-optimal but still effective in achieving the desired motion state, while adhering to kinematic constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If time-optimal trajectories are generated for each actuator independently, then the execution time is minimized, but phase synchronization cannot be achieved which prevents straight-line motion in multi-dimensional space
Solution Approach 1:
The patent applies parameter changes by introducing time-scaling factors and phase-scaling factors to modify the temporal parameters of trajectories. The time-scaling factor adjusts the duration of trajectories to achieve phase synchronization, while phase-scaling factors adjust the phase relationships between actuators. This allows the system to transform time-optimal trajectories into phase-synchronized trajectories that produce straight-line motion, resolving the contradiction between minimizing execution time and achieving phase synchronization precision.
2Manufacturing precision
If phase synchronization is enforced on time-optimal trajectories, then straight-line motion is achieved, but kinematic motion constraints are violated
Solution Approach 1:
The patent applies dynamics by making the trajectory parameters adaptive and adjustable. Instead of using fixed time-optimal trajectories that violate constraints when phase-synchronized, the system dynamically adjusts trajectories using time-scaling and phase-scaling factors. These factors are computed to ensure that phase synchronization is achieved while respecting kinematic motion constraints such as maximum velocity, acceleration, and jerk limits. This dynamic adjustment resolves the contradiction between achieving phase synchronization precision and maintaining reliability through constraint satisfaction.
3Manufacturing precision
If non-real-time trajectory optimization is used, then phase synchronized trajectories can be generated, but real-time adjustment to sensor events and target state changes is not enabled
Solution Approach 1:
The patent applies preliminary action by pre-computing the time-scaling and phase-scaling factors that will be needed for real-time trajectory adjustment. The system establishes the relationships between actuators and computes the scaling factors in advance, based on the robot's kinematic model and constraints. This preliminary computation enables the system to quickly adjust trajectories in real-time by simply applying the pre-computed scaling factors to new target states, rather than performing complex optimization calculations during real-time operation. This resolves the contradiction between achieving phase synchronization precision and maintaining real-time adaptability.
Data Source
AI summary
Methods, apparatus, systems, and computer readable media are provided for generating phase synchronized trajectories for actuators of a robot to enable the actuators of the robot to transition from a current motion state to a target motion state. Phase synchronized trajectories produce motion of a reference point of the robot in a one-dimensional straight line in a multi-dimensional space. For example, phase synchronized trajectories of a plurality of actuators that control the movement of an end effector may cause a reference point of the end effector to move in a straight line in Cartesian space. In some implementations, phase synchronized trajectories may be generated and utilized even when those phase synchronized trajectories are less time-optimal than one or more other non-phase synchronized trajectories.