Purpose This study aims to improve the force sensing performance of robot joint for safety and flexibility physical human–robot interaction. Design/methodology/approach A mechanism (FSM) an S-shaped spring a variable stiffness actuator (VSA) was designed. The yield strength material, geometric assembly structure constraints VSA are all considered deflection limit design. elastic deformation model is solved in reverse obtain local profile S-spring at different angles. manufactured by...

In this article, we propose a novel rotational variable stiffness actuator that uses S-shaped springs as elastic elements. The are designed based on the principle of beam length, which allows for an easily customizable and wide-ranging regulation from minimum value to near infinite. can be smoothly regulated online by rotating springs, resulting in compact mechanism. Moreover, planetary gear differential is used drive mechanism such both control motor main placed at proximal part. This...

This study investigates the impact of various auxiliary cooling techniques on machinability, energy consumption, carbon emissions, and economic factors in drilling process AA7075T6 aluminium alloy using TiO2 C-reinforced composites. The employed conditions (dry, MQL, CO2, hybrid MQL+CO2), with different cutting speeds feed rates, to evaluate their effects characteristics. findings indicated that combined MQL CO2 notably enhanced by reducing forces 32% surface roughness 65% compared dry...

An adaptive robot control approach that can achieve an accurate approximation of the complex dynamics without knowledge unlearning in case multiple sequential tasks is proposed this article. A locally weighted learning (LWL) model with automatic structure growth according to size domain introduced approximate unknown dynamics, and a composite technique regressor extension applied improve parameter convergence. The LWL ensures one area does not cause another area, theoretically guarantees...

In this paper, the supply pressure control problem is studied for a self-supplied variable displacement axial piston pump subjected to unknown time varying load flow disturbance. Due self-supply mechanism of pump, mathematical model demonstrates switching characteristic, in addition, one two subsystems non-minimum phase, which complicates controller design. A strategy uses method output redefinition combined with scheme proposed. By defining new output, system minimum phase respect revised...

In this paper, a novel variable stiffness mechanism (VSM) based on specially designed S-springs made from shape memory alloy (SMA) is developed. Based the model, by changing state combination of SMA with different thicknesses, actuator's can be discretely adjusted online. The adjustment range actuator conveniently extended almost 0 N/m to infinity preset spring angle manually offline without complex mechanical or replacing any parts. A linear digital (LDVSA) also VSM. Some tests S-springs,...

The axle bridge plays a crucial role in the bogie of low-floor light rail vehicles, impacting operational efficiency and fuel economy. To minimize total cost structure turning bridges, an optimization model structural parameters was built, with fatigue life, maximum stress, deformation, main cutting force as constraints. Through orthogonal experiments multivariate variance analysis, key design variables which have significant impact on objectives constraints (performance responses) were...

This study investigates the machining processes of Alloy 20 under different cooling conditions: Minimum Quantity Lubrication (MQL), Carbon Dioxide (CO2), and hybrid MQL + CO2 approach. The research focuses on optimizing cutting parameters, understanding surface characteristics, analysing tool wear patterns, evaluating chip formation. Face-centred CCD-based response methodology (RSM) is applied in order to identify optimized conditions. Surface roughness, wear, morphology are examined through...

由3,4-二羟基肉桂酸(DHCA)与D,L-乳酸(LA) 经熔融缩聚法得到了新型可生物降解聚酯P(DHCA-co-LA)，采用傅立叶变换红外 (FTIR) ，核磁共振（1H-NMR）和凝胶渗透色谱(GPC)对该共聚物的组成与相对分子量进行表征，结果表明其结构明确．改变DHCA与LA单体的配比，得到的P(DHCA-co-LA)的分子量和分子量分布在同一数量级.通过差示扫描量热仪（DSC）、紫外（UV）和荧光光谱研究了共聚物的热性能、紫外与荧光性能，结果表明，P(DHCA-co-LA)有明显的玻璃化转变温度(Tg)，随LA的投料比从0增加至50 mol%时，其Tg从132.26℃下降至99.12℃；当LA的投料比为20 mol%时，所得到的聚酯型共聚物溶液呈现最强的荧光强度；在紫外光照下，共聚物可进行环加成反应，但交联度总体较低；紫外光照65 min后，在荧光显微镜下观察到交联颗粒形态稳定、有较强的荧光．X-射线衍射（XRD）测定结果显示，由结晶性DHCA和LA共聚形成的P(DHCA-co-LA)为无定形聚合物，有利于生物降解．共聚物在土壤中的降解实验表明，其降解速度随体系中LA含量的增加而减缓．

In response to challenges like the complexity and limited scalability of existing variable stiffness joints, a novel joint, based on leaf spring elements, is introduced in this paper. The joint can be adjusted real time by changing effective length via use an Archimedean spiral groove. adjustment range load capacity defined manually configuring number springs involved during offline operations. A model for established cantilever beam theory material mechanics. coupled effects design...

Abstract A novel series of biodegradable copolymers were synthesized by the thermal polycondensation 3,4‐dihydroxycinnamic acid (DHCA) and poly(ethylene glycol) (PEG). The characterized 1 H‐NMR, Fourier transform infrared spectroscopy, gel permeation chromatography. It was found that incorporation PEG reduced glass‐transition temperature ( T g ) copolymers, decreased with increasing amount in compositions. fluorescence spectroscopy revealed homopolymer DHCA gave a higher emission intensity...

A novel energy efficient hydraulic configuration is proposed for force control applications. It can achieve rapid dynamic closed loop response similar to the valve controlled system while maintaining high efficiency as well displacement in steady state. Based on electro-hydraulic configuration, problem addressed. Firstly, simplified mathematical model used design proposed. To deal with inherited uncertainties and unmodelled dynamics, a disturbance observer approximate lumped disturbance. In...

We study the problem of imitation learning in automated decision systems, which a learner is trained to imitate an expert demonstrator. A widely used method adversarial that alternately optimizes generator (learner) and discriminator (reward function). However, biased during initial intermediate training stages. Consequently, gradient descent direction misguided, leads unstable sample complexity. In this paper, we propose deep through guidance-based policy distillation (GIL) algorithm....

Variable stiffness actuators (VSA) are an emerging advanced driving method for robotic joint in physical human-robot interaction scenarios. This paper proposes a VSA based on adjusting the pre-tightening force of ropes by rotating linear springs to change angle its axis relative input frame. By spring within small rotation stroke, between and transmission rope can be changed, thereby achieving rapid adjustment large range. The characteristics analysis shows that proposed has good...

In this paper, the load torque on swashplate of axial piston variable displacement pumps with conical cylinder blocks is studied. At present, general analytical solution for pump not available, which makes dynamic analysis and controller design an uneasy work. The main contribution paper that caused by inertia centrifugal force was derived. First, based acceleration force, kinematic models were developed, addition, chamber pressure dynamics established, distribution in bore under different...

CNC machine tools is the mother of modern industrial manufacture, and spindle core executive mechanism product processing, in order to enhance its application under different working conditions, main shaft electric, pneumatic hydraulic control pipeline often integrated into narrow linear moving Ram, which easily leads fault above-mentioned unit system, normal production enterprise seriously affected. Taking space ram a five-axis as an example, this paper systematically expounds analysis,...