This broad, survey-style background to the state of the art in robot sensing by physical contact achieves its purpose of introducing tactile sensing to the senior undergraduate or graduate student as preparation for later, more in-depth study. The book is short, with 11 short chapters and one longer main chapter on touch sensor arrays.

The first chapter introduces the need for sensing in robots and distinguishes contact and non-contact modalities. It includes locomotion, the additional sensors required for registering the position and orientation of contact sensors, and the supervisory control needed in active sensing. Chapter 2 gives a brief description of human sensing physiology, distinguishing direct (such as thermal) and indirect (such as joint angle) sensing and classifying contact sensor responses. The third chapter defines the terms and parameters of tactile sensing and discusses methods of addressing sensor arrays, including VLSI fabrication. The trend toward preprocessing and computation at the sensor is noted. The fourth chapter briefly presents methods for sensing the position of and force exerted in robot limbs, explaining that these methods are necessary if contact sensor data are to be correctly interpreted. The next two chapters describe sensors for contact forces and surface profiles. Chapter 5 is a substantial chapter devoted to sensor arrays, which covers ranges of methods for a variety of contact modalities for flat surfaces: switching, piezoresistive, piezoelectric (polymers), optical, magnetic, ultrasonic, capacitive, and electrochemical. Chapter 6 extends this to methods for sensing more three-dimensional information, using sensors that comply with external forces, enabling them to sense non-flat surfaces. The next chapter discusses other modes of sensing, including whiskers for proximity sensing, thermal devices, texture sensing by analyzing the vibrations set up when a ridged sensor is drawn across a surface, slip sensing, electrical conductivity for sensing contact resistance, and coupled vibration (for example, for sheep shearing applications where the sensor vibrations are modified by contact between the cutter and the sheep).

Chapter 8 briefly presents a series of points about robot hands that carry contact sensors, discussing gripping, fingers, the human hand, and dexterity. Three examples are described: the Stanford-JPL dextrous hand, the Utah-MIT dextrous hand, and the author’s own Monash gripper, which is interesting because the finger joints are in parallel. Chapter 9 discusses control feedback schemes involving contact sensing, or “reflex level” tactile feedback, which involves low-level feedback from contact sensors to effectors. These schemes include selective compliance and slip detection by image processing of the sensor image. The tenth chapter examines passive pattern matching techniques for recognizing contacted objects. Chapter 11 introduces the possibility of deliberately moving the sensor to provide information to help recognition, for example, to estimate properties of compliance, resilience, pliability, and thermal conductivity. Finally, chapter 12 briefly discusses two approaches to multiple sensing: choosing among the available sensors, and combining different sensing modes into one model.

Unfortunately, the book lacks a concluding chapter. The text makes few recommendations regarding sensing and provides little sensing design advice for the robot system designer. On the other hand, it contains a wealth of material that engineers will be able to use to assist design. The bibliography and exercises at the end of each chapter seem useful, as does the historical material in the text. The content appears somewhat short on the fundamental science associated with each sensing device, and much of it is presented as lists of points, but this presentation is probably appropriate, and other texts will provide fundamentals in each device area. The diagrams are excellent, and include many three-dimensional plots of sensor images. The text gives excellent, simple explanations of sensing devices. Missing is a more comprehensive discussion of higher-level sensory processing. Overall, the book meets a need for a broadly based introduction to robot contact sensing, which includes a wide variety of material about transducer physics, the technology of sensors, and information processing.