Multi-Axis Motor Drive Synchronization Without Communication Delay
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Solution Overview
Problem
Existing motor drive systems experience communication delays when controlling multiple motors in tandem, leading to instability and increased system costs due to the need for high-speed communication channels or reduced bandwidth to accommodate latency.
Innovation Solution
A single motor drive system with integrated axis modules that share state data within a periodic update cycle, eliminating communication latency by synchronizing control loops and using a clock circuit to generate cycle start signals for simultaneous operation of multiple motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If communication channels are used between separate motor drives to coordinate multiple motors, then the motors can work in tandem to control a load, but communication delays and latency are introduced that cause instability and require reduced bandwidth or high-speed communication infrastructure
Solution Approach 1:
The patent combines multiple motor drive functions into a single integrated motor drive system. Multiple axis modules share a common control processor and memory space, allowing them to exchange state data directly without external communication channels. This merging eliminates communication latency while maintaining the ability of multiple motors to work in tandem, as each axis module can access and share data with others instantaneously within the same control cycle.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of shared memory and a common control processor that mediates data exchange between axis modules. Instead of direct communication between separate drives, state data is written to shared memory by one axis module and read by another within the same control cycle, acting as an intermediary that enables instantaneous data transfer without communication delays.
2Loss of time
If high-speed communication channels are established to reduce latency between motor drives, then communication delay is reduced, but system cost increases
Solution Approach 1:
The patent merges multiple motor drive functions into a single integrated system with a common control processor and shared memory. This consolidation eliminates the need for separate high-speed communication channels between drives, as all axis modules operate within the same control environment and can access each other's data instantly without external communication infrastructure, thereby reducing system cost while maintaining low latency.
3Stability of the object's composition
If bandwidth is reduced to accommodate communication delays between motor drives, then system stability is maintained, but control responsiveness deteriorates
Solution Approach 1:
The patent merges multiple axis modules into a single integrated control system where they share a common processor and memory space. This allows all axis modules to execute their control loops simultaneously within the same control cycle and exchange state data instantly without communication delays. As a result, the system maintains high control bandwidth and responsiveness while remaining stable, as there is no communication latency to constrain the update rate.
Data Source
AI summary
A motor controller executes an axis module for each of multiple motors coupled to a shared load. A first control module passes at least one state variable to a second control module without experiencing communication delays between the axis modules. In order to decouple interaction between axes, the first control module determines the desired state variable at a periodic update rate and stores the desired state variable in memory. The first control module provides an indication to the second control module that the desired state variable is available. Within the same period at which the desired state variable is determined, the second control module receives the indication that the desired state variable is available and reads the state variable from the memory of the controller. The second control module executes using the desired state variable to reduce coupling between the two control modules.