[Paper Review] A Domain Specific Language for kinematic models and fast implementations of robot dynamics algorithms

Marco Frigerio, Jonas Buchli+1 more|arXiv (Cornell University)|Jan 30, 2013

Robot Manipulation and LearningEngineering16 references17 citations

TL;DR

This paper proposes a domain-specific language (DSL) for specifying kinematic and dynamic models of rigid-link robots, enabling automatic generation of highly efficient, real-time-compatible code for dynamics algorithms. By abstracting robot models into a high-level DSL, the approach eliminates manual, error-prone coding while producing optimized implementations for controllers and simulators, with proof-of-concept results showing fast inverse dynamics computation.

ABSTRACT

Rigid body dynamics algorithms play a crucial role in several components of a robot controller and simulations. Real time constraints in high frequency control loops and time requirements of specific applications demand these functions to be very efficient. Despite the availability of established algorithms, their efficient implementation for a specific robot still is a tedious and error-prone task. However, these components are simply necessary to get high performance controllers. To achieve efficient yet well maintainable implementations of dynamics algorithms we propose to use a domain specific language to describe the kinematics/dynamics model of a robot. Since the algorithms are parameterized on this model, executable code tailored for a specific robot can be generated, thanks to the facilities available for \dsls. This approach allows the users to deal only with the high level description of their robot and relieves them from problematic hand-crafted development; resources and efforts can then be focused on open research questions. Preliminary results about the generation of efficient code for inverse dynamics will be presented as a proof of concept of this approach.

Motivation & Objective

• Address the challenge of manually implementing high-performance robot dynamics algorithms, which is error-prone and time-consuming.
• Reduce the gap between model-based design and real-time software deployment in robotics by enabling automatic code generation.
• Improve maintainability and portability of robot control software while ensuring real-time efficiency for high-frequency control loops.
• Provide a lightweight, domain-specific solution tailored for rigid-body dynamics, avoiding the overhead of general-purpose modeling tools.
• Free researchers from low-level implementation details to focus on higher-level control and algorithmic innovation.

Proposed method

• Define a domain model that captures only the essential kinematic and dynamic parameters of a robot, such as links, joints, and their physical properties.
• Design a domain-specific language (DSL) based on this model to allow concise, human-readable specification of robot structures.
• Use the DSL to describe robot kinematics and dynamics in a way that is parameterized and amenable to code generation.
• Apply transformation techniques to generate optimized, low-level C or C++ code for dynamics algorithms like inverse dynamics.
• Leverage the DSL's structure to ensure type safety and semantic validation during model authoring.
• Target real-time compatibility by avoiding dynamic memory allocation and system calls in the generated code.

Experimental results

Research questions

• RQ1 Can a domain-specific language effectively abstract robot kinematic and dynamic models to enable automatic, efficient code generation?
• RQ2 How can the DSL reduce the complexity and error rate of implementing robot dynamics algorithms in real-time control systems?
• RQ3 To what extent can the generated code match or exceed the performance of hand-crafted implementations?
• RQ4 Can the DSL support flexible deployment across simulators and real robots with minimal configuration changes?
• RQ5 How can the DSL be extended to support advanced control schemes and complex robot structures like floating-base systems?

Key findings

• The DSL enables high-level, readable specification of robot models without requiring low-level implementation details.
• Proof-of-concept code generation for inverse dynamics algorithms achieves high performance and real-time compatibility.
• The generated code avoids dynamic memory allocation and system calls, satisfying hard real-time constraints.
• The approach significantly reduces the effort required to implement and maintain dynamics algorithms across different robots.
• The DSL infrastructure supports automatic generation of core components like transformation matrices and Jacobians.
• The method demonstrates feasibility for extending to forward dynamics and advanced control frameworks such as operational space control.