Articulated Robot Layout With Base-Mounted Actuators for Heavy Payloads
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Solution Overview
Problem
Articulated robots face limitations in payload capacity and positioning accuracy due to the need to carry drives and power transmission systems, which are heavy and introduce cumulative tolerances along the kinematic chain.
Innovation Solution
A robot design utilizing linear actuators connected to coupling gears to drive arm segments, with the second actuator supported by the first arm segment, allowing for high payload handling and precise movement through optimized transmission characteristics and gimbal bearings to reduce tilting and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If drives and power transmission systems are integrated into the robot arm segments, then the robot achieves high mobility and flexibility, but the payload capacity is limited due to the heavy weight of the drives
Solution Approach 1:
The patent extracts the drives and power transmission systems from the moving robot arm segments and relocates them to the stationary base. This extraction removes the heavy components from the kinematic chain, significantly reducing the weight of moving parts and increasing payload capacity while maintaining full mobility and flexibility through the linear actuators that extend from the base.
2Adaptability or versatility
If multiple arm links are arranged serially to achieve high mobility, then flexibility is improved, but positioning accuracy deteriorates due to cumulative tolerances
Solution Approach 1:
The patent segments the traditional rotary joint structure into separate functional components: linear actuators provide precise linear motion control from the base, while coupling gears convert this motion to arm segment rotation. This segmentation allows each component to be optimized independently, reducing cumulative tolerances while maintaining the flexibility of multiple serial arm links.
Solution Approach 2:
The coupling gears act as intermediaries between the linear actuators and the arm segments. These gears provide a precise mechanical interface that converts linear actuator motion into accurate rotational motion of the arm segments, reducing the impact of tolerances and improving overall positioning accuracy while preserving system flexibility.
3Weight of moving object
If linear actuators are used to drive arm segments from the base, then payload capacity is improved, but the workspace and reach are reduced
Solution Approach 1:
The patent extends the linear actuators in a downward direction from the base, utilizing the vertical dimension rather than horizontal space. This allows the actuators to provide full payload support while the arm segments maintain their full horizontal reach and workspace, effectively decoupling payload capacity from workspace dimensions.
4Manufacturing precision
If coupling gears are used to connect linear actuators to arm segments, then transmission characteristics are optimized for precision, but device complexity increases
Solution Approach 1:
The patent uses identical coupling gear designs for all arm segment connections. This homogenization of the transmission interface simplifies manufacturing and assembly while maintaining precise motion transmission. The standardized coupling gears reduce complexity through repeatability and modularity, even though multiple transmission interfaces are required.
Data Source
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AI summary
The invention relates to an articulated robot for handling a payload, comprising a robotic arm, which is secured to a base (1) that can rotate about a first axis (AI) and which has at least two arm elements (2, 3) arranged in series one after another in the form of a kinematic chain and a central hand (4Z) attached at the end of the kinematic chain. A first (2) of the two arm elements (2, 3) arranged one after another is mounted on the base such that it can swivel about a second axis (A2) running transverse to the first axis (AI), in particular orientated orthogonally relative to the first axis (AI), whereas a second arm element (3) is arranged on the first arm element (2) such that it can swivel about a third axis (A3). Articulated robots are versatile and widely used industrial robots, with kinematics formed from multiple arm elements connected to one another in an articulated manner, in order to position end effectors, e.g. grippers or tools. Robots with series kinematics have particularly high mobility and flexibility, given that each arm element is serially connected to only one further arm element. However, articulated robots of this type are limited in terms of their load capacity at the end of the arm due to the need for drives and force-transmission systems to be carried along, and in terms of their positioning accuracy due to the summation effect of tolerances along the kinematic chain.