Parallel Kinematics Robot Rotational Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional parallel kinematics robots face limitations in providing rotational degrees of freedom to the end effector due to increased weight and restricted work area, as existing solutions either add weight to the kinematic chain or limit the movement with cardan universal joints.
Innovation Solution
The use of kinematic chains responsible for translational movements as support structures for rotational movements, incorporating gear wheels and levers to enable rotational degrees of freedom without limiting the translational movements, and utilizing revolute pairs to integrate rotational and translational kinematic chains without adding inertia or restricting the work area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional actuator is arranged between two rods in the kinematic chain, then the end effector gains rotational degree of freedom, but the weight of the kinematic chain increases and the servo motor cannot move as fast
Solution Approach 1:
The patent combines the rotational actuation system with the existing translational kinematic chain by integrating the additional actuator into the structure of the drive arm or rod assembly. This merging approach allows the rotational degree of freedom to be added without creating a completely separate heavy mechanism, thereby reducing the overall weight increase compared to traditional approaches.
Solution Approach 2:
The patent designs the kinematic chain elements to serve multiple functions: the drive arms and rods not only provide translational movement but also support the rotational actuation mechanism. This multi-functionality reduces the need for additional dedicated structural components, thereby minimizing weight increase while achieving both translational and rotational capabilities.
2Adaptability or versatility
If three additional servo motors are arranged at the base of the robot, then the end effector gains three rotational degrees of freedom, but the work area is strongly limited by the largest allowed inclination of the transmission members
Solution Approach 1:
The patent resolves the work area limitation by moving the rotational actuation from the base level to the kinematic chain level, where it can operate in a different spatial dimension. This dimensional shift allows the rotational joints to function independently of the base-mounted cardan joints, eliminating the work area restrictions imposed by cardan joint inclination limits.
Solution Approach 2:
The patent extracts the rotational actuation function from the base-mounted cardan joint system and relocates it to the kinematic chain itself. This extraction removes the constraint of cardan joint inclination angles from the system, as the new rotational joints are not subject to the same geometric limitations, thereby expanding the robot's work area.
3Adaptability or versatility
If additional actuators and transmission members are added to provide rotational movements, then the end effector gains rotational capability, but the complexity of the kinematic chain increases
Solution Approach 1:
The patent merges the rotational actuation system with the existing translational kinematic chain structure, integrating the additional actuators and transmission members into the existing framework rather than adding completely separate systems. This integration approach minimizes the increase in overall system complexity by sharing structural and control resources.
Solution Approach 2:
The patent designs the kinematic chain elements to perform multiple functions simultaneously - the drive arms and rods provide both translational and rotational actuation. This multi-functionality reduces the total number of dedicated components needed, thereby limiting the increase in device complexity while achieving enhanced capability.
Data Source
AI summary
A parallel kinematics robot includes a base and an end effector movable in relation to the base. A first actuator is attached to the base and connected to the end effector via a first kinematic chain including a first drive arm, a first rod, a first joint between the first drive arm and the first rod, and a second joint between the first rod and the end effector. A second actuator is attached to the base and connected to the end effector via a second kinematic chain including a second drive arm, a second rod, a third joint between the second drive arm and the second rod, and a fourth joint between the second rod and the end effector. A third actuator is attached to the base or to the first drive arm, and connected to the end effector via a third kinematic chain including a first gear wheel and a second gear wheel, the first and second gear wheels being journalled in bearings to the end effector and intermeshing with each other. One element of the third kinematic chain constitutes a kinematic pair with at least one element of the first kinematic chain. A kinematic chain responsible for a translational movement of the end effector is utilized as a support structure for a kinematic chain responsible for a rotational movement of the end effector.