Parallel Link Robot Actuator via Cable Transmission
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Solution Overview
Problem
Existing parallel link robots face limitations in increasing degrees of freedom without narrowing the operational range and compromising acceleration/deceleration performance, particularly due to constraints in drive shaft length, universal joint interference, and vulnerability to corrosive environments.
Innovation Solution
A parallel link robot design featuring a base, moving part, and three links with additional actuators between driven links, utilizing a power transmission shaft to transmit rotational force to a posture changing mechanism, which includes features like through holes and key/spline configurations to enhance flexibility and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an extendable drive shaft is used to increase the fourth degree of freedom, then the robot can perform more complex tasks, but the operational range is limited by the drive shaft length
Solution Approach 1:
The patent replaces the traditional mechanical extendable drive shaft with a flexible cable system. The cable can be wound and unwound to provide extended operational range while maintaining compact storage, eliminating the length limitations of rigid extendable shafts.
Solution Approach 2:
The patent introduces a winding mechanism that adds a rotational dimension to the cable deployment system. By winding the cable around a drum, the system achieves compact storage while maintaining extended linear reach, effectively adding a dimensional solution to the length constraint.
2Adaptability or versatility
If a universal joint is used in the drive shaft, then the robot can accommodate base and movable plate position changes, but the universal joint interferes with other parts at large bending angles
Solution Approach 1:
The patent replaces the universal joint mechanism with a flexible cable system that naturally accommodates angular changes without mechanical joints. The cable's flexibility allows it to bend and adapt to position changes without interfering with surrounding components.
Solution Approach 2:
The patent uses a flexible cable instead of rigid mechanical joints. The cable can bend and deform to accommodate changes in the relative positions of the base and movable plate without requiring universal joints that would interfere with other parts.
3Adaptability or versatility
If an actuator is directly arranged on the movable plate to increase degrees of freedom, then the mounting member can turn easily, but the movable plate's acceleration and deceleration performance is remarkably limited
Solution Approach 1:
The patent replaces the direct mechanical coupling of an actuator on the movable plate with a cable-driven system. The cable transmits force remotely, allowing the mounting member to rotate without adding significant mass to the movable plate, thereby preserving acceleration and deceleration performance.
Solution Approach 2:
The patent introduces a cable as an intermediary between the actuator and the mounting member. This allows the actuator to be positioned away from the movable plate, transmitting rotational force through the cable without directly increasing the movable plate's mass and inertia.
4Adaptability or versatility
If the movable plate is exposed to corrosive solutions, then the robot can operate in certain environments, but the actuator may be splashed and malfunction
Solution Approach 1:
The patent replaces the traditional actuator mounted on the movable plate with a cable-driven system where the actuator is positioned away from the corrosive environment. The cable transmits force through the harsh environment without the actuator being directly exposed, maintaining reliability.
Solution Approach 2:
The cable serves as an intermediary that transmits force from the actuator through the corrosive environment to the mounting member. This allows the actuator to remain in a protected position while still enabling operation in corrosive environments, as the cable itself is resistant to corrosion.
Data Source
AI summary
A parallel link robot (10) provided with a base (11), a moving part (12), three links (20a to 20c) coupling the base and the moving part and having respectively single degrees of freedom with respect to the base, and three actuators (13a to 13c) respectively driving the links, each of the links comprised of a drive link (21a to 21c) coupled with the base and two driven links (22a to 22c, 23a to 23c) coupling the drive link and the moving part and parallel to each other, and further provided with a posture changing mechanism (15) which changes a posture of an element (19) attached to the moving part, an additional actuator (13d to 13f) arranged between the two driven links of at least one link in parallel to these driven links, and a power transmission shaft (39) which extends coaxially from the additional actuator and transmits rotational drive force to the posture changing mechanism. Due to this, it is possible to increase the degrees of freedom without reducing the possible region of operation and the acceleration/deceleration performance.