International Journal of Hydromechatronics (10 papers in press)

Regular Issues

• Determination of the flow rate characteristics of porous media under the positive pressure and vacuum  
  by Wei Zhong, Yihao Wang, Kaiwen Fu, Chong Li, Jiang Shao, Pengfei Qian 
  Abstract: Porous media is widely used to replace the conventional orifices as restrictors in vacuum handling process. In this study, a theoretical model describing the flow rate characteristics, including effects from both viscosity and inertia, is established based on Darcy-Forchheimer’s law. The simulation work is firstly conducted, followed by establishing apparatuses to determine permeability and inertial coefficients. The permeability is determined within a small pressure difference (< 2 kPa) and the inertial coefficient is obtained with Re > 0.1 as the boundary. The average permeability is 1.21 × 10^-12 m² , 1.56 × 10^-12 m² , 3.41 × 10^-12 m² and 12.21 × 10^-12 m² , respectively. The inertial coefficient is determined under the positive pressure at the maximum pressure difference and vacuum with pressure difference from 50 kPa to 70 kPa. For different pressure conditions, it is confirmed that the theoretical flow rate can predict the experimental data within a 3% uncertainty which is sufficient for most applications. Finally, to obtain the inertial coefficient, two methods including the single-point method and the multi-point method are proposed. We found that the single-point method gives an error of 3.1% while the multi-point method gives an error of 1.9% for the determination of the entire flow rate characteristics.
  Keywords: flow rate characteristics; porous media; positive pressure; vacuum; permeability; inertial coefficient.
  DOI: 10.1504/IJHM.2024.10062649
   
  
• Design and modelling of multiple-air-chamber pneumatic soft bending actuators  
  by Xin Liu, Jinhui Zhang, Zheng Li, Shaomeng Gu, Ling Zhao, Bo Liu 
  Abstract: In this paper, we design a multiple-air-chamber pneumatic soft bending actuator made of two-component silicone rubber that can achieve angle bending at any direction in space. Both the design philosophy and the working principle of the multiple-air-chamber pneumatic soft bending actuator are described in detail. Additionally, the dynamic model of the multiple-air-chamber pneumatic soft bending actuator is established by dividing the bending angle into n segments and using the Euler-Lagrange method. By simulating the dynamic model, we can find the optimal number of segments n that achieve desired angle bending control performance. Finally, experimental results of angle bending control for step signal and sinusoidal signal verify that the dynamic model is effective and applicative to obtain desired angle bending control performance.
  Keywords: pneumatic soft bending actuator; dynamic model; angle bending.
  DOI: 10.1504/IJHM.2023.10066215
   
  
• Dynamic characteristics of rotary magnetorheological fluid brake for use with air turbine spindle  
  by Vanisara Kaewnamchai, Tomonori Kato, Yuki Mihashi 
  Abstract: Air turbine spindles are widely used in various machines, such as milling tools and aspherical lens generators. This study aimed to investigate the potential use of commercially available rotary magnetorheological fluid (MRF) brakes as components to effectively regulate the rotational speed of air turbine spindles in the low rotation-speed range from 100 to 500 min1. The target speed was set as 300 min1 with response time set to 20 s after the speed reached the target. Accordingly, a Hall Effect magnetic sensor was used to measure the low-to-high rotation speed of the air turbine spindle in addition to the magnetic induction generated by the current supply of the MRF brake. Tests were conducted to obtain the rotation speed, resistance torque, magnetic field, and electrical power supply in a commercial MRF brake used to control the shaft of the air turbine spindle. The results show that commercial MRF brake can effectively control the rotation speed in the low-speed region. However, the dynamic characteristic of the MRF brake cause undesirable oscillations.
  Keywords: air turbine spindle; experimental analysis; dynamic characteristic; functional fluid; pneumatic measurement; rotation speed control.
  DOI: 10.1504/IJHM.2024.10066216
   
  
• A closed-loop evaluation identification algorithm for rubber mixing process based on physical information and deep learning  
  by Xueyang Bai, Jiguang Yue, Ruiqi Guan, Zhexin Cui, Rongyan Li 
  Abstract: Rubber mixing process is a crucial link in tyre manufacturing. Accurate mixing model will greatly affect the control performance, thus affecting the final yield and quality of tyres. However, due to the complexity of the mixing process, there is still a great challenge to establish an accurate mixing process model. In this paper, a closed-loop evaluation identification algorithm for mixing model is proposed. On the basis of the state space model established by heat transfer mechanism, the unknown parameters are identified based on CNN-LSTM deep network. A fuzzy evaluation method is utilised to comprehensively evaluate the identification effect in view of the lack of uniform evaluation indexes. The GRU network is used to correct the error of identification results. The deep neural network hyperparameters are iteratively updated based on the genetic optimisation algorithm to achieve the feedback optimisation. Finally, simulation verifies the effectiveness and merits of the proposed algorithm.
  Keywords: parameter identification; rubber mixing; bond graph; deep learning; fuzzy evaluation.
  DOI: 10.1504/IJHM.2024.10067758
   
  
• Robust active disturbance rejection control for modular fluidic soft actuators  
  by Yunce Zhang, Tao Wang, Xuqu Hu 
  Abstract: Delicate dynamic control of soft actuators is a challenging task due to their strongly nonlinearities. This article focuses on the dynamic control of the modular fluidic soft actuators governed by pneumatic proportional valves. Since it is difficult to accurately describe the complex coupling relationships among the chambers of the soft actuators, the dynamic control of the soft actuators cannot be implemented by using advanced control algorithms based on precise model in usual. To improve the manipulability and extend the application scenarios, we design a robust active disturbance rejection control method based on linear extended state observer, which only requires an approximate model of the soft actuators. Experimental results show that closed-loop stability and good tracking performance are achieved by the proposed method, meanwhile better disturbance rejection ability is guaranteed in comparison to the commonly used proportional-integral-differential control method.
  Keywords: controller design; state observation; dynamic performance; fluidic power; modular soft actuators.
  DOI: 10.1504/IJHM.2023.10059853
   
  
• Low-pulsation design of motion structure in cam-lobe hydraulic motor  
  by Chao Zhang, Yiman Duan, Pengpeng Dong, Hao Tan, Xiaolong Zhang, Min Han, Zhijian Zheng, Junhui Zhang, Bing Xu 
  Abstract: Cam-lobe hydraulic motors are widely used in high-end equipment due to their low speed and high output torque. The motion structure composed of piston assemblies and cam ring is the key component that converts hydraulic power into mechanical rotational speed, which directly affects the hydraulic motor rotational speed pulsation. Yet, there is little research on the low-pulsation motion structure design. For that, this study proposed the low-pulsation design approach of motion structure to achieve the hydraulic motor with good speed stability. In general, the piston assembly number and the action number design should ensure that the total angle distribution coefficient is not less than 2, but it should be greater than 3 when the asymmetric distribution coefficient is 2. Finally, several hydraulic motors are used to validate the effectiveness of the low-pulsation design. This study can provide theory guidelines for the low-pulsation motion structure design.
  Keywords: hydraulic motors; low-pulsation; motion structure; cam ring curve; speed stability.
  DOI: 10.1504/IJHM.2024.10067913
   
  
• Crack propagation control for a pre-stressed concrete beam utilising coupled sensitivity indices-Pareto optimisation method  
  by Nazim Abdul Nariman 
  Abstract: A coupled Sobol’s sensitivity indices and Pareto optimisation method was dedicated to determine an optimum prediction model of a pre-stressed concrete beam to control the crack propagation. Five variables were deployed which belong to the mechanical properties of the concrete and the reinforcement steel bars in addition to the pre-stressing one. The BoxBehnken sampling method was used with numerical simulations by ABAQUS program and the support of MATLAB codes. The pre-stressing variable manifested the greatest influence on the crack propagation compared to the rest variables. Furthermore, the optimised values of all variables produced the minimum tensile damage 0.164 compared to the three cases of the highest total sensitivity indices of pre-stressing variable which were 0.946, 0.788, and 0.631 respectively. Consequently, the coupled method confirmed excellent efficiency in creating a robust tool to control the crack propagation and predict the behavior of the structural system to an outstanding accuracy.
  Keywords: tendon; concrete damage plasticity; main impact; interaction impact; objective function; ABAQUS.
  DOI: 10.1504/IJHM.2024.10065461
   
  
• Enhancing position control in pneumatic systems using ANFIS and high-speed on-off valves with compound PWM  
  by Guoxin Sun, Shuaipeng Li, Qihui Yu, Jiabao Zhang 
  Abstract: In the context of position servo control utilising compressed air as the primary power source, the challenge of achieving precise control while maintaining economic efficiency remains a central concern. Addressing the issue of the significant reliance on manual expertise in designing fuzzy controllers, we propose the implementation of an adaptive neuro-fuzzy inference system (ANFIS) to enhance fuzzy control through the integration of neural networks. This innovation entails the substitution of costly proportional valves with cost-effective high-speed on-off valves and the replacement of traditional pulse width modulation (PWM) with compound PWM. These adaptations serve to significantly extend the operational lifespan of the on-off valves. This strategic approach amalgamates the learning capabilities of neural networks with the reasoning aptitude of fuzzy logic, effectively addressing the intricate nonlinear characteristics inherent to pneumatic systems. Empirical findings underscore the effectiveness of this strategy, with step response overshoot below 3.1%, steady-state error less than 0.5%, steady-state error below 0.22 mm for square wave signals, relative root mean square error (RRMSE) less than 1.50 mm for harmonic signals, and robust tracking performance observed across diverse loads and high-pressure gas sources.
  Keywords: adaptive neuro-fuzzy inference system; ANFIS; high-speed on-off valve; pulse width modulation; compound PWM; position control.
  DOI: 10.1504/IJHM.2024.10064700
   
  
• Diffusion-based degradation in silicon photovoltaic solar cells  
  by Ankur Singh, P.R. Budarapu 
  Abstract: Due to moisture affinity of polymers, the water diffusion in photovoltaic (PV) is inevitable, resulting degradation and corrosion of the module. In this study, the water diffusion and hence, the degradation of PV modules has been investigated. The water concentration in the PV module considering varying environmental conditions has been studied through simulations. The presence of water vapour in PV solar cells leads to corrosion of metallic parts in the presence of atmospheric oxygen. In a PV cell, galvanic corrosion occurs in the presence of diffused water, where water acts as an electrolyte, and soldering material and metallic parts acts as anode and cathode materials, respectively. The galvanic corrosion results in the generation of electro-chemical current, which finally leads to the deformation of metallic parts. The influence of water diffusion on the galvanic corrosion in metallic parts is estimated through simulations, using COMSOL multiphysics computational tool.
  Keywords: photovoltaic modules; water diffusion; Fickian diffusion model; back sheet; corrosion.
  DOI: 10.1504/IJHM.2024.10066606
   
  
• Linear active disturbance rejection motion control of a novel pneumatic actuator with linear-rotary compound motion  
  by Yifan Jia, Zhihao Zhang, Shan Du, Wei Zhong, Yuantong Xu, Chenwei Pu, Luis Miguel Ruiz Páez, Pengfei Qian 
  Abstract: Linear and rotary motions are two commonly encountered forms of motion in practical industrial applications. However, the research on pneumatic actuators with linear-rotary compound motion is limited, and the existing actuators cannot meet the actual motion requirements. In this regard, this paper develops a novel pneumatic actuator capable of realizing linear and rotary compound motions based on pneumatic cylinders and pneumatic motors. Two proportional directional valves are employed to control the displacement of the linear motion module and the rotational speed of the rotary motion module respectively. A linear active disturbance rejection (LADRC) controller for the novel pneumatic actuator with linear-rotary compound motion is developed in this paper by adopting a non-model-based active disturbance rejection control algorithm. Experimental results indicate that with the LADRC controller, the steady-state error in trajectory tracking is less than 1 mm, and the steady-state error in speed control is within 3.4 rpm.
  Keywords: linear-rotary compound motion; pneumatic actuator; linear active disturbance rejection control; LADRC; position tracking control; rotational speed control.
  DOI: 10.1504/IJHM.2024.10066636