Towards a universal end effector : the design and development of production technology's intelligent robot hand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Engineering and Automation at Massey University

Research into robot hands for industrial use began in the early 1980s and there are now many examples of robot hands in existence. The reason for research into robot hands is that standard robot end effectors have to be designed for each application and are therefore costly. A universal end effector is needed that will be able to perform any parts handling operation or use other tools for other industrial operations. Existing robot hand research would therefore benefit from new concepts, designs and control systems. The Department of Production Technology is developing an intelligent robot hand of a novel configuration, with the ultimate aim of producing a universal end effector. The concept of PTIRH (Production Technology's Intelligent Robot Hand) is that it is a multi-fingered manipulator with a configuration of two thumbs and two fingers. Research by the author for this thesis concentrated on five major areas. First, the background research into the state of the art in robot hand research. Second, the initiation, development and analysis of the novel configuration concept of PTIRH. Third, specification, testing and analysis of air muscle actuation, including design, development and testing of a servo pneumatic control valve for the air muscles. Fourth, choice of sensors for the robot hand, including testing and analysis of two custom made air pressure sensors. Fifth, definition, design, construction, development, testing and analysis of the mechanical structure for an early prototype of PTIRH. Development of an intelligent controller for PTIRH was outside the scope of the author's research. The results of the analysis on the air muscles showed that they could be a suitable direct drive actuator for an intelligent robotic hand. The force, pressure and position sensor results indicate that the sensors could form the basis of the feedback loop for an intelligent controller. The configuration of PTIRH enables it to grasp objects with little reliance on friction. This was demonstrated with an early prototype of the robot hand, which had one finger with actuation and three other static digits, by successfully manually arranging the digits into stable grasps of various objects

Developing shape change-based fashion prototyping strategies:Enhancing computational thinking in fashion practice and creativity

Emerging technologies enable fluid and versatile material forms of fashionable wearables and e-textiles, with experts in engineering and material science proposing numerous strategies for dynamic textile and garment structures to satisfy various needs. Nevertheless, a critical gap remains in developing practical fashion prototyping strategies that fuse with computational thinking to challenge current norms and envision the future of fashion. This study introduces shape change-based fashion prototyping as a design strategy for dynamic expressions and affordances to inspire fashion practitioners’ interdisciplinary endeavors. We present three studio-based practices as case studies to demonstrate how shape-changing mechanisms including servo motors, shape memory alloys, and pneumatics, spur new fashion construction skills and broaden the scope of potential applications. By doing so, this study contributes to material and conceptual innovation, creating pathways for the seamless integration of technologies from conceptualization, and implementation to envision. Our findings shed light on design possibilities and challenges and offer design recommendations that guide future endeavors. The implications of our research underscore the importance of adopting a relational approach to design variables, emphasize the value of fostering shared vocabulary between fashion and technical design, and highlight the transformative potential of shape-changing prototyping in reshaping the intricate body-material relationship.</p

A Characterization of Actuation Techniques for Generating Movement in Shape-Changing Interfaces

Abstract This article characterizes actuation techniques for generating movement in shape-changing displays with physically reconfigurable geometry. To date, few works in Human Computer Interaction literature provide detailed and reflective descriptions of the implementation techniques used in shape-changing displays. This hinders the rapid development of novel interactions as researchers must initially spend time understanding technologies before prototyping new interactions and applications. To bridge this knowledge gap, we propose a taxonomy that classifies actuator characteristics and simplifies the process for designers to select appropriate technologies that match their requirements for developing shape-displays. We scope our investigation to linear actuators that are used in grid configurations. The taxonomy is validated by (a) examining current implementation techniques of motorized, pneumatic, hydraulic, magnetic, and shape-memory actuators in the literature, (b) constructing prototypes to address limited technical details and explore actuator capabilities in depth, (c) describing a use-case scenario through a case study that details the construction of a 10 ? 10 actuator shape-display, and (d) a set of guidelines to aid researchers in selecting actuation techniques for shape-changing applications. The significance of our taxonomy is twofold. First, we provide an original contribution that enables HCI researchers to appropriately select actuation techniques and build shape-changing applications. This is situated amongst other past works that have investigated broader application scenarios such as a shape-changing vocabulary, a framework for shape transformations, material properties, and technical characteristics of various actuators. Second, we carry out in-depth investigations to validate our taxonomy and expand the knowledge of vertical actuation in shape-changing applications to enable rapid development

A Review of Pneumatic Actuators Used for the Design of Medical Simulators and Medical Tools

International audienc

Pneumatic Artificial Muscle Driven Trailing Edge Flaps For Active Rotors

This research focuses on the development of an active rotor system capable of primary control and vibration reduction for rotorcraft. The objective is to investigate the feasibility of a novel Trailing Edge Flap (TEF) actuation system driven by Pneumatic Artificial Muscles (PAMs). A significant design effort led to a series of experimental apparatuses which tested various aspects of the performance of the actuators themselves and of TEF systems driven by them. Analytical models were developed in parallel to predict the quasistatic and dynamic behavior of these systems. Initial testing of a prototype blade section with an integrated PAM driven TEF proved the viability of the concept through successful benchtop testing under simulated M = 0.3 loading and open jet wind tunnel tests under airspeeds up to M = 0.13. This prototype showed the ability of PAM actuators to generate significant flap deflections over the bandwidth of interest for primary control and vibration reduction on a rotorcraft. It also identified the importance of high pneumatic system mass flow rate for maintaining performance at higher operating frequencies. Research into the development and improvement of PAM actuators centered around a new manufacturing technique which was invented to directly address the weaknesses of previous designs. Detailed finite element model (FEM) analysis of the design allowed for the mitigation of stress concentrations, leading to increased strength. Tensile testing of the swaged actuators showed a factor of safety over 5, and burst pressure testing showed a factor of safety of 3. Over 120,000,000 load cycles were applied to the actuators without failure. Characterization testing before, during, and after the fatigue tests showed no reduction in PAM performance. Wind tunnel testing of a full scale Bell 407 blade retrofitted with a PAM TEF system showed excellent control authority. At the maximum wind tunnel test speed of M = 0.3 and a derated PAM operating pressure of 28 psi, 18.8° half-peak-to-peak flap deflections were achieved at 1/rev (7 Hz), and 17.1° of half-peak-to-peak flap deflection was still available at 5/rev (35 Hz). A quasistatic system model was developed which combined PAM forces, kinematics and flap aerodynamics to predict flap deflection amplitudes. This model agreed well with experimental data. Whirl testing of a sub-span whirl rig under full scale loading conditions showed the ability of PAM TEF systems to operate under full scale levels of centrifugal (CF), aerodynamic, and inertia loading. A commercial pneumatic rotary union was used to provide air in the rotating frame. Extrapolation of the results to 100% of CF acceleration predicts 15.4° of half-peak-to-peak flap deflection at 1/rev (7 Hz), and 7.7° of half-peak-to-peak flap deflection at 5/rev (35 Hz). A dynamic model was developed which successfully predicted the time domain behavior of the PAM actuators and PAM TEF system. This model includes control valve dynamics, frictional tubing losses, pressure dynamics, PAM forces, mechanism kinematics, aerodynamic hinge moments, system stiffness, damping, and inertia to solve for the rotational dynamics of the flap. Control system development led to a closed loop control system for PAM TEF systems capable of tracking complex, multi-sinusoid flap deflections representative of a combined primary control and vibration reduction flap actuation scheme. This research shows the promise that PAM actuators have as drivers for trailing edge flaps on active helicopter rotors. The robustness, ease of integration, control authority and tracking accuracy of these actuators have been established, thereby motivating further research

Design, fabrication and control of soft robots

Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.National Science Foundation (U.S.) (Grant IIS-1226883

Variable Friction Device for Structural Control based on Duo-Servo Vehicle Brake: Modeling and Experimental Validation

Supplemental damping can be used as a cost-effective method to reduce structural vibrations. In particular, passive systems are now widely accepted and have numerous applications in the field. However, they are typically tuned to specific excitations and their performances are bandwidth-limited. A solution is to use semi-active devices, which have shown to be capable of substantially enhanced mitigation performance. The authors have recently proposed a new type of semi-active device, which consists of a variable friction mechanism based on a vehicle duo-servo drum brake, a mechanically robust and reliable technology. The theoretical performance of the proposed device has been previously demonstrated via numerical simulations. In this paper, we further the understanding of the device, termed Modified Friction Device (MFD) by fabricating a small scale prototype and characterizing its dynamic behavior. While the dynamics of friction is well understood for automotive braking technology, we investigate for the first time the dynamic behavior of this friction mechanism at low displacements and velocities, in both forward and backward directions, under various hydraulic pressures. A modified 3-stage dynamic model is introduced. A LuGre friction model is used to characterize the friction zone (Stage 1), and two pure stiffness regions to characterize the dynamics of the MFD once the rotation is reversed and the braking shoes are sticking to the drum (Stage 2) and the rapid build up of forces once the shoes are held by the anchor pin (Stage 3). The proposed model is identified experimentally by subjecting the prototype to harmonic excitations. It is found that the proposed model can be used to characterize the dynamics of the MFD, and that the largest fitting error arises at low velocity under low pressure input. The model is then verified by subjecting the MFD to two different earthquake excitations under different pressure inputs. The model is capable of tracking the device׳s response, despite a lower fitting performance under low pressure and small force output, as it was found in the harmonic tests due to the possible nonlinearity in Stage 2 of the model

3D printed pneumatic soft actuators and sensors: their modeling, performance quantification, control and applications in soft robotic systems

Continued technological progress in robotic systems has led to more applications where robots and humans operate in close proximity and even physical contact in some cases. Soft robots, which are primarily made of highly compliant and deformable materials, provide inherently safe features, unlike conventional robots that are made of stiff and rigid components. These robots are ideal for interacting safely with humans and operating in highly dynamic environments. Soft robotics is a rapidly developing field exploiting biomimetic design principles, novel sensor and actuation concepts, and advanced manufacturing techniques. This work presents novel soft pneumatic actuators and sensors that are directly 3D printed in one manufacturing step without requiring postprocessing and support materials using low-cost and open-source fused deposition modeling (FDM) 3D printers that employ an off-the-shelf commercially available soft thermoplastic poly(urethane) (TPU). The performance of the soft actuators and sensors developed is optimized and predicted using finite element modeling (FEM) analytical models in some cases. A hyperelastic material model is developed for the TPU based on its experimental stress-strain data for use in FEM analysis. The novel soft vacuum bending (SOVA) and linear (LSOVA) actuators reported can be used in diverse robotic applications including locomotion robots, adaptive grippers, parallel manipulators, artificial muscles, modular robots, prosthetic hands, and prosthetic fingers. Also, the novel soft pneumatic sensing chambers (SPSC) developed can be used in diverse interactive human-machine interfaces including wearable gloves for virtual reality applications and controllers for soft adaptive grippers, soft push buttons for science, technology, engineering, and mathematics (STEM) education platforms, haptic feedback devices for rehabilitation, game controllers and throttle controllers for gaming and bending sensors for soft prosthetic hands. These SPSCs are directly 3D printed and embedded in a monolithic soft robotic finger as position and touch sensors for real-time position and force control. One of the aims of soft robotics is to design and fabricate robotic systems with a monolithic topology embedded with its actuators and sensors such that they can safely interact with their immediate physical environment. The results and conclusions of this thesis have significantly contributed to the realization of this aim