**9.1. Robotic systems based on vulcanized FFAs**

#### *9.1.1. Modular flexible fluidic drive elements*

These drives are based on the ∅36 *mm* actuator. Integrated in the modules are the valves and one position sensor (AS5045-austriamicrosystems) as well as two pressure sensors (MS5803-14BA-measurement specialties) (figure 31).

**Figure 31.** Highly Integrated Flexible Fluidic Drive Module

The modules can be combined in several parallel and serial configurations. Hence the torque-angle characteristics can be varied and adjusted to the case of operation, which is presented in figure 32-34.

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Dynamic testing has shown that after 100, 000 cycles, no visible damage is present. Static testing has also been described in earlier work [36]. The properties have found to be extraordinary with operating loads up to 100*N* and a maximum carrying capacity of over 3, 000*N*. The enhanced fabrication process for flexures allows for the production of single-acting (mass 9.1 *g*) and double-acting (mass 11.6 *g*) drives with full integration of the flexible fluidic actuator as well as the position sensor as described in [36]. Figure 30 shows the different joint-modules. These modules now can be freely combined as shown in figure 35.

A large amount of robotic systems with flexible fluidic actuators have been developed over the last ten years. This is represented in many publications and patents [35, 65, 66, 108–111, 113–116]. These systems come from fields such as prosthetics, orthotics, medical devices as well as humanoid robotics and automation. Here some of the latest developments in the fields

These drives are based on the ∅36 *mm* actuator. Integrated in the modules are the valves and one position sensor (AS5045-austriamicrosystems) as well as two pressure sensors

(b) Double-Acting composite flexure

Plug-In Valve

Circuit Board with Pressure Sensor

Diametrically Polarized Magnet

drive

(a) Single-Acting composite flexure

**Figure 30.** Different Designs for Composite Flexure Drives in Robots

of vulcanized and HF-welded actuators are presented.

**9.1. Robotic systems based on vulcanized FFAs**

(MS5803-14BA-measurement specialties) (figure 31). Connector

> Hall-Encoder for Angular Measurement

**Figure 31.** Highly Integrated Flexible Fluidic Drive Module

*9.1.1. Modular flexible fluidic drive elements*

drive

**9. Applications**

**Figure 32.** Single Drive Module

**Figure 33.** Double Module - Parallel Configuration

**Figure 34.** Double Module - Serial Configuration

#### 32 Will-be-set-by-IN-TECH 598 Smart Actuation and Sensing Systems – Recent Advances and Future Challenges

#### *9.1.2. Three-fingered composite gripper*

The fiber reinforced flexure hinges are combined to form a three-fingered gripper as shown in figure 35. The base of this gripper is built of three double-acting flexure drives. Each finger is designed with two single acting flexure drives. The base of the gripper has three main positions. These positions are for spherical, cylindrical and precision grasping (figure 35). However, the compliance of the gripper allows a large variety of grasps. Figure 36 shows the taxonomy of the different grasps. The total weight of the gripper is 400 *g*. Each finger has a length of 140 *mm*.

**Figure 35.** Main Base Positions of the Composite Gripper

**Figure 36.** Grasp Taxonomy of the Composite Gripper

#### *9.1.3. Lightweight Robotic Arm (LRA)*

The drive modules, compliant structural elements, and the composite gripper have modular interfaces and can be combined freely. To evaluate the whole system a 6 DOF arm has been designed and built (figure 37). The proximal joint consists of two combined drive modules in parallel configuration. The weight of the whole arm is 3.45 *kg* and has a total length of 735 *mm*. 598 Smart Actuation and Sensing Systems – Recent Advances and Future Challenges Compliant Robotics and Automation with Flexible Fluidic Actuators and Inflatable Structures <sup>33</sup> Compliant Robotics and Automation with Flexible Fluidic Actuators and In atable Structures 599

**Figure 37.** Lightweight Robotic Arm

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The fiber reinforced flexure hinges are combined to form a three-fingered gripper as shown in figure 35. The base of this gripper is built of three double-acting flexure drives. Each finger is designed with two single acting flexure drives. The base of the gripper has three main positions. These positions are for spherical, cylindrical and precision grasping (figure 35). However, the compliance of the gripper allows a large variety of grasps. Figure 36 shows the taxonomy of the different grasps. The total weight of the gripper is 400 *g*. Each finger has a

Parallel

(a) (b) (c) (d) (e) (f)

(g) (h) (i) (j) (k)

The drive modules, compliant structural elements, and the composite gripper have modular interfaces and can be combined freely. To evaluate the whole system a 6 DOF arm has been designed and built (figure 37). The proximal joint consists of two combined drive modules in parallel configuration. The weight of the whole arm is 3.45 *kg* and has a total length of 735 *mm*.

(d) Precision

*9.1.2. Three-fingered composite gripper*

(a) Overview (b) Spherical (c)

**Figure 35.** Main Base Positions of the Composite Gripper

**Figure 36.** Grasp Taxonomy of the Composite Gripper

*9.1.3. Lightweight Robotic Arm (LRA)*

length of 140 *mm*.
