Elastic Actuator Control with Internal State Model Fallback
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Solution Overview
Problem
Conventional robots operating in close proximity to humans face challenges with safety due to their rigid mechanisms and require continuous operation without immediate shutdown in case of sensor malfunctions, which existing control methods struggle to address effectively.
Innovation Solution
A control apparatus and method for an elastic actuator drive mechanism that includes an abnormality determination unit, normal case operation control unit, and abnormal case operation control unit, allowing the system to switch between normal and abnormal operation modes based on sensor output, using internal state models to ensure continuous and safe operation even when sensor measurements are faulty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a robot operates in close proximity to humans with rigid mechanisms, then positioning accuracy is improved, but safety deteriorates
Solution Approach 1:
The patent replaces rigid mechanical structures with flexible elastic actuators that can deform and adapt to human contact. The elastic actuator uses an elastic body that can be compressed and expanded, providing inherent compliance and safety when operating near humans while still achieving precise positioning through controlled deformation.
Solution Approach 2:
The patent employs pneumatic actuators that use compressed gas to drive the elastic body. This pneumatic system provides smooth, compliant motion without the rigid mechanical linkages of traditional robots, enabling safe human-robot interaction while maintaining positioning accuracy through pressure control.
2Manufacturing precision
If a robot uses electric motor with feedback control, then positioning accuracy is improved, but flexibility deteriorates
Solution Approach 1:
The patent substitutes traditional electric motors and mechanical transmission systems with elastic actuators driven by pneumatic pressure. This replacement eliminates rigid mechanical components while maintaining actuation capability, providing both flexibility in motion and positioning accuracy through controlled elastic deformation.
3Object-affected harmful factors
If a robot immediately stops operation upon sensor malfunction, then safety is improved, but productivity deteriorates
Solution Approach 1:
The patent pre-stores operation data and internal state models in memory before any malfunction occurs. When a sensor malfunction is detected, the system immediately switches to using this pre-stored data to maintain operation, avoiding shutdown while ensuring safety through fallback control based on previously captured system states.
Solution Approach 2:
The patent creates a virtual copy of the sensor data from pre-stored operation data when the actual sensor malfunctions. This copied data allows the control system to continue operating as if the sensor were functioning normally, maintaining productivity while the physical sensor defect is addressed.
Data Source
AI summary
There is provided an abnormality determination unit that determines whether or not an output measurement unit is abnormal, in order to determine abnormality of the output measurement unit. When the output measurement unit is abnormal, the operation of an elastic actuator is controlled not in accordance with a measurement result of the output measurement unit but in accordance with an internal state model.