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Item type:Publication, Access status: without files , Remote control of a soft walking robot(2021-04-12); This paper develops an intuitive user interface in order to operate a gecko-inspired soft robot remotely by using a joystick. The developed method enables the operation of the comparatively fast robot by the untrained human user, which is a further step towards making the robot usable for industrial applications.Publicationtype: Conference Paper28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A gait pattern generator for closed-loop position control of a soft walking robot(2020-07-02); ; This paper presents an approach to control the position of a gecko-inspired soft robot in Cartesian space. By formulating constraints under the assumption of constant curvature, the joint space of the robot is reduced in its dimension from nine to two. The remaining two generalized coordinates describe respectively the walking speed and the rotational speed of the robot and define the so-called velocity space. By means of simulations and experimental validation, the direct kinematics of the entire velocity space (mapping in Cartesian task space) is approximated by a bivariate polynomial. Based on this, an optimization problem is formulated that recursively generates the optimal references to reach a given target position in task space. Finally, we show in simulation and experiment that the robot can master arbitrary obstacle courses by making use of this gait pattern generator.Publicationtype: Journal ArticleScopus© Citations 6 179 183 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Manufacturing, control, and performance evaluation of a gecko-inspired soft robot(2020-06-01); ; This protocol presents a method for manufacturing, control, and evaluation of the performance of a soft robot that can climb inclined flat surfaces with slopes of up to 84°. The manufacturing method is valid for the fast pneunet bending actuators in general and might, therefore, be interesting for newcomers to the field of actuator manufacturing. The control of the robot is achieved by means of a pneumatic control box that can provide arbitrary pressures and can be built by only using purchased components, a laser cutter, and a soldering iron. For the walking performance of the robot, the pressure-angle calibration plays a crucial role. Therefore, a semi-automated method for the pressure-angle calibration is presented. At high inclines (> 70°), the robot can no longer reliably fix itself to the walking plane. Therefore, the gait pattern is modified to ensure that the feet can be fixed on the walking plane.Publicationtype: Journal ArticleScopus© Citations 1 162 251 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A lightweight simulation model for soft robot's locomotion and its application to trajectory optimizationThis letter extends the piecewise constant curvature modeling approach by energy minimization techniques in order to simulate contact with the environment. The new method enables a fast and sufficiently good estimation of the forward kinematics for soft structures whose behavior is mainly determined by boundary conditions. This enables to predict the configuration of such structures for a given reference input, which is demonstrated on a gecko-inspired soft robot. The newly gained simulation capability is then used to find new patterns for straight as well as curved trotting gait. The existing gait pattern for straight gait could be improved by a factor of 1.4, and a new gait pattern for the rotation on the spot could be discovered.Publicationtype: Journal Article77 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Kit based motion generator for a soft walking robotIn order to control high-level goals such as walking speed and direction or position of legged robots, a locomotion controller is required. This complicated task can be solved in many different ways. The approach presented here selects the optimal gait pattern from a discrete, predefined set of possibilities to get closer to a given target position. The method is based on an off-line component: elementary gait patterns are generated by trajectory optimization using a simulation model, and an on-line component: for given robot and target positions the optimal next elementary gait pattern is chosen based on a minimization problem, and the joint space references are derived from it. To ensure feasible subsequent poses, the elementary patterns always begin and end with one and the same pose, so that they can be placed on top of each other like Lego bricks. A great advantage of this method is a straightforward transition between different motion modes, such as switching from trotting to crawling. It is discussed how many different elementary patterns are needed to ensure a stable locomotion control. Finally, in simulation and experiment, it is shown that the robot can master any obstacle course using the proposed locomotion controller.Publicationtype: Conference Paper68 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Toward a gecko-inspired, climbing soft robotIn this paper, we present a gecko-inspired soft robot that is able to climb inclined, flat surfaces. By changing the design of the previous version, the energy consumption of the robot could be reduced, and at the same time, its ability to climb and its speed of movement could be increased. As a result, the new prototype consumes only about a third of the energy of the previous version and manages to climb slopes of up to 84◦. In the horizontal plane, its velocity could be increased from 2 to 6 cm/s. We also provide a detailed analysis of the robot's straight gait.Publicationtype: Journal ArticleScopus© Citations 28 241 269 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A simple control strategy for increasing the soft bending actuator performance by using a pressure boostHigh-speed actuation of soft actuators requires high source pressure to transfer air as quickly as possible into the actuator. Allowing high source pressure and having the deformation angle as the only control input may allow faster actuation, but there is a risk of bursting when the actuator is prevented from reaching the desired angle, for example, due to an obstacle. The other option to control the actuator’s deformation is based on controlling the pressure. In this paper, we present a simple control strategy that uses an initial pressure boost in a pressure-based PID controller showing the same performance as in angle-based PID control. The performance improvement is demonstrated experimentally on a standard soft bending actuator and a gecko-inspired, climbing soft robot.Publicationtype: Conference Paper148 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Entwicklung eines Laufmusters und Entwurf einer weichen Laufmaschine nach biologischem VorbildDevelopment of a gait pattern and design of a soft robot according to a biological model: This paper presents the theoretical basis for the linear gait of a soft robot. This gait pattern is derived from the movement of a gecko. Furthermore, it is illustrated how the developed gait pattern can be realized in a soft machine.Publicationtype: Conference Paper44 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Integrated curvature sensing of soft bending actuators using inertial measurement unitsWe introduce a sensor concept for an integrated measurement of the curvature angle of soft bending actuators using inertial measurement units (IMUs). In particular, IMUs are placed at both ends of the soft bending actuator, and the integrated magnetic sensors are used for small and the integrated acceleration sensors for medium and large inclination angles of the soft actuator’s bending plane. The experimental results show absolute measurement errors of up to 20◦ for small and less than 5◦ for medium and large inclination angles. Furthermore, we investigate experimentally whether the assumption of a constant curvature in our sensor concept is still fulfilled when the soft bending actuator is loaded by an external force at its free end. The results indicate that this is the case for loading masses of up to 30 g at large inclination angles.Publicationtype: Conference Paper240