RobotLocomotion/drake
Nov 2024 – Feb 2026
12 Months active
Languages Used
C++PythonBazelMarkdown
Technical Skills
C++C++ DevelopmentConstraint ParsingConstraint ProgrammingConvex OptimizationDrake
Hongkai Dai
PROFILE
Hongkai Dai
Over twelve months, contributed to RobotLocomotion/drake by developing and refining core optimization, robotics, and simulation features. Delivered enhancements such as improved SDP/LMI constraint handling, granular cost function updates, and expanded Python bindings for deformable geometry APIs. Addressed solver robustness and reproducibility by updating constraint parsing, introducing trajectory optimization sparsity patterns, and implementing detailed test coverage. Leveraged C++, Python, and Bazel to ensure efficient build systems, reliable numerical optimization, and cross-language support. The work emphasized maintainability and correctness, with targeted bug fixes in inverse kinematics and trajectory generation, and comprehensive documentation to streamline onboarding and development workflows across the codebase.
Overall Statistics
Feature vs Bugs
83%Features
Repository Contributions
37Total
Bugs
4
Commits
37
Features
19
Lines of code
5,357
Activity Months12
Your Network
35 peopleShared Repositories
35
Work History
February 2026
1 Commits • 1 Features
Feb 1, 2026February 2026 (2026-02) monthly summary for RobotLocomotion/drake: Delivered a flexible IK enhancement by introducing an optional p_BQ decision variable in PositionConstraint. Updated constructors, evaluation paths, and tests to support the new parameter, enabling users to search over p_BQ (in frame B) as a decision variable and expanding the inverse kinematics configuration space. This work improves modularity and experimentation capability in IK and prepares the codebase for more advanced constraint formulations. No major bug fixes were reported this month for this repo.
1 Commits • 1 Features
Feb 1, 2026February 2026 (2026-02) monthly summary for RobotLocomotion/drake: Delivered a flexible IK enhancement by introducing an optional p_BQ decision variable in PositionConstraint. Updated constructors, evaluation paths, and tests to support the new parameter, enabling users to search over p_BQ (in frame B) as a decision variable and expanding the inverse kinematics configuration space. This work improves modularity and experimentation capability in IK and prepares the codebase for more advanced constraint formulations. No major bug fixes were reported this month for this repo.
February 2026
October 2025
2 Commits • 2 Features
Oct 1, 2025October 2025 monthly summary for RobotLocomotion/drake focusing on feature deliveries, testing, and cross-language support. Two key features were delivered with full binding support and unit tests, expanding beneficiary coverage across the modeling pipeline and data interchange workflows.
October 2025
2 Commits • 2 Features
Oct 1, 2025October 2025 monthly summary for RobotLocomotion/drake focusing on feature deliveries, testing, and cross-language support. Two key features were delivered with full binding support and unit tests, expanding beneficiary coverage across the modeling pipeline and data interchange workflows.
September 2025
1 Commits
Sep 1, 2025September 2025: Delivered a critical correctness fix for Differential Inverse Kinematics (DiffIK) in the Drake repository by including the previously omitted constant term c in the VᵀV least-squares cost, restoring the full quadratic cost. This change improves optimization accuracy and reliability of IK solutions in motion planning and simulation, reducing divergence risks and producing more predictable trajectories. The patch (commit 0dd03e02b426712071a4a7a98502c210d0fc9900) was implemented under 'Add the constant term in DiffIK least squares cost. (#23442)'.
1 Commits
Sep 1, 2025September 2025: Delivered a critical correctness fix for Differential Inverse Kinematics (DiffIK) in the Drake repository by including the previously omitted constant term c in the VᵀV least-squares cost, restoring the full quadratic cost. This change improves optimization accuracy and reliability of IK solutions in motion planning and simulation, reducing divergence risks and producing more predictable trajectories. The patch (commit 0dd03e02b426712071a4a7a98502c210d0fc9900) was implemented under 'Add the constant term in DiffIK least squares cost. (#23442)'.
September 2025
August 2025
1 Commits • 1 Features
Aug 1, 2025August 2025 — Drake: Delivered a comprehensive VSCode C++ clangd setup and compile_commands.json guidance to enable semantic analysis and autocompletion for Drake's codebase. Includes install steps for clangd, VSCode configuration, and generation of compile_commands.json via the bazel-compile-commands-extractor branch, with error handling and regeneration after changes. No major bugs fixed this month. Impact: accelerates contributor onboarding, standardizes local development, and improves code navigation and editor reliability across Drake. Technologies demonstrated: C++, clangd, VSCode, Bazel, compile_commands.json workflow, and documentation/operational guidance.
August 2025
1 Commits • 1 Features
Aug 1, 2025August 2025 — Drake: Delivered a comprehensive VSCode C++ clangd setup and compile_commands.json guidance to enable semantic analysis and autocompletion for Drake's codebase. Includes install steps for clangd, VSCode configuration, and generation of compile_commands.json via the bazel-compile-commands-extractor branch, with error handling and regeneration after changes. No major bugs fixed this month. Impact: accelerates contributor onboarding, standardizes local development, and improves code navigation and editor reliability across Drake. Technologies demonstrated: C++, clangd, VSCode, Bazel, compile_commands.json workflow, and documentation/operational guidance.
July 2025
1 Commits
Jul 1, 2025July 2025 (RobotLocomotion/drake): Stabilized trajectory reset behavior in SchunkWsgTrajectoryGenerator. Fixed initialization of trajectory_start_time to infinity and added regression tests for resets across system resets and context changes. This work enhances reliability and reduces risk of stale trajectories in both simulations and deployments. References: commit cf4243b9a0e4737b33065ad62b8885627b07a060 (#23196).
1 Commits
Jul 1, 2025July 2025 (RobotLocomotion/drake): Stabilized trajectory reset behavior in SchunkWsgTrajectoryGenerator. Fixed initialization of trajectory_start_time to infinity and added regression tests for resets across system resets and context changes. This work enhances reliability and reduces risk of stale trajectories in both simulations and deployments. References: commit cf4243b9a0e4737b33065ad62b8885627b07a060 (#23196).
July 2025
May 2025
6 Commits • 2 Features
May 1, 2025May 2025 monthly work summary focusing on delivering core capabilities for deformable geometry workflows, simulator configurability, and solver robustness within Drake (RobotLocomotion/drake). Delivered Python bindings for deformable geometry API in pydrake, introduced a start_time parameter in SimulatorConfig for reproducible simulations, and hardened solver behavior for Mosek and OSQP to improve reliability and diagnosability under infeasibility or numerical issues. Included tests where applicable to verify new bindings and configurations.
May 2025
6 Commits • 2 Features
May 1, 2025May 2025 monthly work summary focusing on delivering core capabilities for deformable geometry workflows, simulator configurability, and solver robustness within Drake (RobotLocomotion/drake). Delivered Python bindings for deformable geometry API in pydrake, introduced a start_time parameter in SimulatorConfig for reproducible simulations, and hardened solver behavior for Mosek and OSQP to improve reliability and diagnosability under infeasibility or numerical issues. Included tests where applicable to verify new bindings and configurations.
April 2025
3 Commits • 2 Features
Apr 1, 2025April 2025 monthly summary for RobotLocomotion/drake focusing on performance and reliability improvements in optimization and solver option handling. Delivered two key features that reduce runtime and increase configurability, supported by targeted tests and commits.
3 Commits • 2 Features
Apr 1, 2025April 2025 monthly summary for RobotLocomotion/drake focusing on performance and reliability improvements in optimization and solver option handling. Delivered two key features that reduce runtime and increase configurability, supported by targeted tests and commits.
April 2025
March 2025
1 Commits • 1 Features
Mar 1, 2025March 2025 — RobotLocomotion/drake: Implemented gradient sparsity pattern support for velocity constraints in Kinematic Trajectory Optimization, refactored WrappedVelocityConstraint for explicit gradient sparsity, and added CheckGradientSparsityPattern utility. These changes improve efficiency, testability, and scalability of trajectory optimization; committed as 6129a37187c48550b08df633d0c464afd00b1b6c (KinTrajOpt AddVelocityConstraint).
March 2025
1 Commits • 1 Features
Mar 1, 2025March 2025 — RobotLocomotion/drake: Implemented gradient sparsity pattern support for velocity constraints in Kinematic Trajectory Optimization, refactored WrappedVelocityConstraint for explicit gradient sparsity, and added CheckGradientSparsityPattern utility. These changes improve efficiency, testability, and scalability of trajectory optimization; committed as 6129a37187c48550b08df633d0c464afd00b1b6c (KinTrajOpt AddVelocityConstraint).
February 2025
2 Commits • 1 Features
Feb 1, 2025February 2025 performance summary for RobotLocomotion/drake focusing on trajectory optimization enhancements and solver improvements. Delivered robust velocity constraints within KinematicTrajectoryOptimization, expanded the quadratic constraint solver with a new HessianType::kZero and improved handling for indefinite Hessians when trace is zero, and refreshed Python bindings and unit tests to cover the new capabilities. No major bugs reported this month; effort prioritized reliability, maintainability, and extended planning capabilities.
2 Commits • 1 Features
Feb 1, 2025February 2025 performance summary for RobotLocomotion/drake focusing on trajectory optimization enhancements and solver improvements. Delivered robust velocity constraints within KinematicTrajectoryOptimization, expanded the quadratic constraint solver with a new HessianType::kZero and improved handling for indefinite Hessians when trace is zero, and refreshed Python bindings and unit tests to cover the new capabilities. No major bugs reported this month; effort prioritized reliability, maintainability, and extended planning capabilities.
February 2025
January 2025
1 Commits
Jan 1, 2025This month focused on stabilizing the Ipopt-based optimization workflow in Drake. Delivered a bug fix to IpoptSolver tolerance, updated tests and solver configurations, and reinforced CI coverage to ensure long-term stability. The changes were committed to RobotLocomotion/drake (commit 962483669d015ee2618585ace2c884598fbadbb5).
January 2025
1 Commits
Jan 1, 2025This month focused on stabilizing the Ipopt-based optimization workflow in Drake. Delivered a bug fix to IpoptSolver tolerance, updated tests and solver configurations, and reinforced CI coverage to ensure long-term stability. The changes were committed to RobotLocomotion/drake (commit 962483669d015ee2618585ace2c884598fbadbb5).
December 2024
4 Commits • 3 Features
Dec 1, 2024December 2024 monthly wrap-up for RobotLocomotion/drake highlighting key feature deliveries, bug fixes, and technical accomplishments that drive business value and engineering velocity. Focused on solver robustness, reproducibility tooling, and post-creation cost configurability, enabling faster iteration and clearer debugging across optimization workflows.
4 Commits • 3 Features
Dec 1, 2024December 2024 monthly wrap-up for RobotLocomotion/drake highlighting key feature deliveries, bug fixes, and technical accomplishments that drive business value and engineering velocity. Focused on solver robustness, reproducibility tooling, and post-creation cost configurability, enabling faster iteration and clearer debugging across optimization workflows.
December 2024
November 2024
14 Commits • 6 Features
Nov 1, 2024Consolidated 2024-11 as a productivity and reliability milestone for Drake's optimization stack. Key features delivered include: SDP/LMI constraint handling improvements with 2x2 PSD/LMI parsed as SOC, support for small 1x1 and 2x2 LMIs, new LMI APIs, and expanded tests; reliable dual-solution reporting for PSD/LMI constraints across Mosek, SCS, and Clarabel with correct scaling and ordering; gradient sparsity patterns added for LorentzConeConstraint and RotatedLorentzConeConstraint to boost solver throughput; granular cost API updates for LinearCost and QuadraticCost enabling precise coefficient/constant/Hessian updates; internal performance improvements via vector-based variable extraction and centralized warning handling. Major bug fix: MosekSolver PSD parsing bug with repeated variableResolved.
November 2024
14 Commits • 6 Features
Nov 1, 2024Consolidated 2024-11 as a productivity and reliability milestone for Drake's optimization stack. Key features delivered include: SDP/LMI constraint handling improvements with 2x2 PSD/LMI parsed as SOC, support for small 1x1 and 2x2 LMIs, new LMI APIs, and expanded tests; reliable dual-solution reporting for PSD/LMI constraints across Mosek, SCS, and Clarabel with correct scaling and ordering; gradient sparsity patterns added for LorentzConeConstraint and RotatedLorentzConeConstraint to boost solver throughput; granular cost API updates for LinearCost and QuadraticCost enabling precise coefficient/constant/Hessian updates; internal performance improvements via vector-based variable extraction and centralized warning handling. Major bug fix: MosekSolver PSD parsing bug with repeated variableResolved.
Activity
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Quality Metrics
Correctness96.0%
Maintainability93.0%
Architecture93.0%
Performance89.8%
AI Usage20.0%
Skills & Technologies
Programming Languages
BazelC++MarkdownPython
Technical Skills
BindingsBuild SystemsC++C++ DevelopmentC++ developmentConstraint ParsingConstraint ProgrammingControl SystemsConvex OptimizationDocumentationDrakeEigenGeometry ProcessingIDE ConfigurationLinear Algebra
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