Remote Hydraulic Joint Actuation for Torque-Speed Balance
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Solution Overview
Problem
Existing actuation systems for robotic joints fail to balance high torque generation with speed and safety, particularly in interactions with humans, and require multiple actuators for each joint, leading to inefficiencies in industrial applications.
Innovation Solution
A system using a combination of hydraulic and pneumatic actuators with elastic elements, allowing for high torques at low frequencies and moderate torques at high frequencies, while ensuring safety and reducing inertia, and enabling a single actuator to control multiple joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high mechanical impedance actuators (gearmotors, hydraulic cylinders) are used to produce sufficient torques, then torque generation capability is improved, but safety in human interaction deteriorates and actuation band is reduced
Solution Approach 1:
The patent employs a hydrostatic transmission system that uses hydraulic fluid to transmit force from a remote actuator to the robotic joint. This allows the actuator to generate high torque while the hydraulic fluid provides compliance and safety during human interaction, resolving the contradiction between force generation and safety
Solution Approach 2:
The hydrostatic transmission acts as an intermediary between the actuator and the robotic joint, providing mechanical compliance and safety. The hydraulic fluid serves as a mediator that transmits force while allowing controlled compliance, enabling safe human interaction while maintaining high torque capability
2Force
If high mechanical impedance actuators are used to support robot weight, then torque/force capability is improved, but actuation speed and dexterity deteriorate
Solution Approach 1:
The hydrostatic transmission enables high actuation speeds by using hydraulic fluid to transmit force rapidly from the remote actuator to the joint, while maintaining the torque capability through the same hydraulic system, thus resolving the speed-torque trade-off
3Force
If multiple actuators are used for each robotic joint, then torque generation capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent implements a universal actuation system where a single remote actuator can control multiple robotic joints through a shared hydrostatic transmission system. This multi-functional approach eliminates the need for separate actuators for each joint, reducing system complexity while maintaining torque generation capability
4Ease of manufacture
If hydrostatic transmission is used for remote actuation, then integration simplicity and modularity are improved, but balance between speed and torque controllability deteriorates
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor the hydrostatic transmission system's performance and adjust actuator commands in real-time. This enables precise control of both speed and torque during dynamic operations, resolving the controllability balance issue while maintaining integration simplicity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves high-speed movement with accurate positioning and force control, ensuring safety in human interactions and reducing the number of actuators needed, thus optimizing performance and cost-efficiency.
Implementation Method 1
a hydraulic transmission comprising, for each actuated group, a first hydraulic line and a second hydraulic line arranged to actuate said or each receiving hydraulic cylinder in order to generate a mechanical action on the mechanical joint proportional to a pressure difference ΔP=P1−P2
Implementation Method 2
said or each actuation group comprising a first actuator arranged to actuate said or each transmission hydraulic cylinder in order to generate a pressure difference ΔP=ΔPL, whose main feature is that said or each actuation group also comprises a second actuator arranged to actuate said or each transmission hydraulic cylinder in order to generate a pressure difference ΔP=ΔPH>5*ΔPL
Data Source
AI summary
A system for the remote actuation of articulated mechanisms comprising at least one actuated group comprising a mechanical joint having at least one degree of freedom and at least one receiving hydraulic cylinder connected to the mechanical joint. The system also comprises a hydraulic transmission comprising, for each actuated group, a first hydraulic line and a second hydraulic line arranged to actuate each receiving hydraulic cylinder in order to generate a mechanical action on the mechanical joint proportional to a pressure difference ΔP=P1−P2, where P1 is the fluid pressure in the first hydraulic line and P2 is the fluid pressure in the second hydraulic line.