Height Control and Optimal Torque Planning for Jumping With Wheeled-Bipedal Robots
Pith reviewed 2026-05-07 15:59 UTC · model grok-4.3
The pith
Wheeled-bipedal robots achieve precise jump heights through Bayesian-optimized continuous torque profiles that also cut energy use.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The authors claim that the W-JBD dynamical model supplies usable initial torque curves, which the BOTP method then refines into continuous optimal profiles; the resulting plans deliver accurate height control together with lower energy cost, as shown by an 82.3 percent drop in height error and 26.9 percent drop in energy use when tested on the Webots platform.
What carries the argument
The BOTP (Bayesian optimization for torque planning) method, which uses the W-JBD model to shrink the torque search space and then optimizes smooth profiles without needing an exact dynamic model.
Load-bearing premise
Simulation results from Webots will transfer to physical robots and the optimized torque profiles will stay near-optimal when friction, motor delays, and sensor noise are present.
What would settle it
Apply the same continuous torque curves on a physical wheeled-bipedal robot and check whether height error remains reduced by at least 70 percent relative to the unoptimized baseline.
Figures
read the original abstract
This paper mainly studies the accurate height jumping control of wheeled-bipedal robots based on torque planning and energy consumption optimization. Due to the characteristics of underactuated, nonlinear estimation, and instantaneous impact in the jumping process, accurate control of the wheeled-bipedal robot's jumping height is complicated. In reality, robots often jump at excessive height to ensure safety, causing additional motor loss, greater ground reaction force and more energy consumption. To solve this problem, a novel wheeled-bipedal jumping dynamical model(W-JBD) is proposed to achieve accurate height control. It performs well but not suitable for the real robot because the torque has a striking step. Therefore, the Bayesian optimization for torque planning method(BOTP) is proposed, which can obtain the optimal torque planning without accurate dynamic model and within few iterations. BOTP method can reduce 82.3% height error, 26.9% energy cost with continuous torque curve. This result is validated in the Webots simulation platform. Based on the torque curve obtained in the W-JBD model to narrow the searching space, BOTP can quickly converge (40 times on average). Cooperating W-JBD model and BOTP method, it is possible to achieve the height control of real robots with reasonable times of experiments.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. This paper claims to solve the problem of accurate height control for jumping wheeled-bipedal robots by proposing a wheeled-bipedal jumping dynamical model (W-JBD) that enables precise control but produces discontinuous torques unsuitable for hardware. To address this, it introduces the Bayesian optimization for torque planning (BOTP) method, which is largely model-free and yields continuous optimal torque curves. In Webots simulations, BOTP reduces height error by 82.3% and energy cost by 26.9%, converging in about 40 iterations on average when the search space is narrowed using the W-JBD model. The authors assert that this combination makes real-robot height control feasible with a reasonable number of experiments.
Significance. The results, if they hold under hardware conditions, represent a meaningful advance in control strategies for underactuated robotic jumping systems by combining model-based insights with model-free optimization to produce practical torque plans. The reported quantitative gains in accuracy and efficiency, along with the rapid convergence of BOTP, highlight the potential of Bayesian optimization in robotics applications where accurate models are hard to obtain. Credit is due for the simulation-based validation showing clear improvements.
major comments (2)
- [Abstract] The reported performance improvements of 82.3% in height error and 26.9% in energy cost are presented without any information on the baseline methods, the number of trials, statistical significance, or the methods used to measure jumping height and energy consumption. This omission undermines the ability to fully assess the validity and reproducibility of the central quantitative claims.
- [Abstract] The final claim that the W-JBD model and BOTP method together 'achieve the height control of real robots with reasonable times of experiments' lacks any supporting evidence from physical robot experiments. The validation is confined to the Webots simulation platform, with no analysis of sim-to-real transfer, robustness to uncertainties (e.g., friction variations, motor delays, sensor noise), or calibration data, which is a load-bearing gap for the paper's broader applicability assertion.
minor comments (1)
- [Abstract] The description of BOTP as operating 'without accurate dynamic model' is slightly inconsistent with the use of the W-JBD model to narrow the searching space; a brief clarification on the degree of model dependency would improve clarity.
Simulated Author's Rebuttal
We thank the referee for the constructive comments and the positive evaluation of the work's significance. We address each major comment below and will revise the manuscript to improve clarity and accuracy.
read point-by-point responses
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Referee: [Abstract] The reported performance improvements of 82.3% in height error and 26.9% in energy cost are presented without any information on the baseline methods, the number of trials, statistical significance, or the methods used to measure jumping height and energy consumption. This omission undermines the ability to fully assess the validity and reproducibility of the central quantitative claims.
Authors: We agree that the abstract should include more context on these elements to support the claims. The baseline is the direct torque planning from the W-JBD model. The improvements are obtained from repeated Webots simulations with results averaged over multiple runs, height measured from the simulated robot's kinematic state, and energy computed as the time integral of electrical power. We will revise the abstract to briefly note the baseline, the simulation-based nature of the evaluation, and the measurement methods, while referring readers to the results section for trial counts and any statistical details. revision: yes
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Referee: [Abstract] The final claim that the W-JBD model and BOTP method together 'achieve the height control of real robots with reasonable times of experiments' lacks any supporting evidence from physical robot experiments. The validation is confined to the Webots simulation platform, with no analysis of sim-to-real transfer, robustness to uncertainties (e.g., friction variations, motor delays, sensor noise), or calibration data, which is a load-bearing gap for the paper's broader applicability assertion.
Authors: We acknowledge that the manuscript contains only simulation results and no hardware experiments. The statement is an extrapolation from the rapid convergence of BOTP (approximately 40 iterations) when the search space is narrowed by the W-JBD model. We agree this claim requires qualification. We will revise the abstract to state that the approach shows promise for real-robot height control with a reasonable number of experiments, subject to future hardware validation. We will also add discussion of sim-to-real considerations, including sensitivity to friction, delays, and noise, based on our simulation analyses. revision: yes
Circularity Check
No circularity; claims rest on independent simulation experiments
full rationale
The paper introduces the W-JBD model and BOTP method as original contributions. Height-error and energy reductions (82.3 % and 26.9 %) are measured outcomes of running BOTP inside the external Webots simulator, not quantities derived by algebraic substitution from the model equations themselves. Narrowing the BOTP search space with W-JBD torque curves is a heuristic that still leaves the optimizer free to produce new continuous profiles; the reported convergence count (40 iterations) and performance deltas are therefore empirical results, not tautological re-statements of the inputs. No self-citations appear in the provided text, and no fitted parameter is relabeled as a prediction. The forward claim about real-robot feasibility is an untested extrapolation rather than a circular derivation step.
Axiom & Free-Parameter Ledger
invented entities (1)
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W-JBD model
no independent evidence
Reference graph
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