Device for the passive haptic representation of the compliance of objects

Abstract

The invention relates to a device for the passive haptic representation of the compliance of objects comprising • a tactile surface; • a printing stamp; • a support structure; • a pressure actuator; and • a deformation actuator; wherein the tactile surface has a non-deformable contact surface and flexibly deformable contact surface edges laterally relative to the non-deformable contact surface. The tactile surface is configured to deform the deformable contact surface edges under the control of the deformation actuator such that the tactile surface assumes a U-shape. Furthermore, the pressure plunger is controllable by the pressure actuator, and the pressure plunger and the deformable contact surface edges are controllable independently of one another. Furthermore, the invention encompasses a system comprising the device according to the invention and a method for passively haptically displaying the compliance of objects.

Description

[0001] The invention relates to a device for the passive haptic representation of the compliance of objects comprising • a tactile surface; • a printing stamp; • a support structure; • a pressure actuator; and • a deformation actuator; wherein the tactile surface has a non-deformable contact surface and flexibly deformable contact surface edges laterally to the non-deformable contact surface. The tactile surface is configured to deform the deformable contact surface edges, controlled by the deformation actuator, such that the tactile surface assumes a U-shape. Furthermore, the pressure plunger is controllable by the pressure actuator, and the pressure plunger and the deformable contact surface edges are controllable independently of one another. Furthermore, the invention encompasses a system comprising the device according to the invention and a method for the passive haptic representation of the compliance of objects.

[0002] The haptic perception of the resilience of objects and their surfaces is an essential source of information for humans in many application areas. If an interaction takes place with objects that are out of reach of the hands, they cannot be interacted with directly, and thus the resilience of these objects cannot be directly perceived via the sensory receptors in the hands and fingers. This can occur, for example, in the field of teleoperation or laparoscopic surgery. In laparoscopic surgery, which is a minimally invasive method, an intervention in the abdominal cavity is performed using rod-shaped surgical instruments (laparoscopes). The instruments used have a 20 to 30 cm long rod between the effector and the operating handle. The instruments are inserted into the abdominal cavity through a small incision.The surgeon does not have free access to the tissue and cannot touch it directly with his or her fingers. Therefore, haptic perception of the tissue's flexibility is not possible. Teleoperations are performed by remote-controlled robots. The surgical tools are operated by a robotic arm, so the same limitations regarding the haptic perception of objects (tissue) and flexibility arise in this area as already described for laparoscopic surgery.

[0003] Another area where direct haptic perception through the hands is not possible is the entire realm of virtual reality. The flexibility of virtual objects, such as those presented through VR headsets, cannot be perceived by humans. The experience of virtual reality would become significantly more realistic if supplemented by the haptic perception of the flexibility of objects touched in virtual reality.

[0004] However, the highly dynamic passive haptic representation of soft and hard objects and surfaces remains a major challenge, which has so far only been partially implemented. There are four relevant cues derived from haptic stimuli that must be correctly recreated: (1) Kinesthetic cues (resistance to object contact) (2) Vibrotactile cues (vibration by collision), (3) Skin deformation cues (deformation of the skin due to pressure) and (4) Skin tactile surface cues (sinking of body parts such as a finger into a soft object or a soft surface, whereby the effective contact area between object and finger increases).

[0005] To date, only acceptable technical solutions exist for the representation of kinesthetic cues, vibrotactile cues, and skin deformation cues. A simple, technically feasible representation of the variable skin contact area across a wide compliance range, which can be combined with the aforementioned cues, does not yet exist. However, this would be necessary, particularly in the fields of telerobotics, minimally invasive surgery or telesurgery, or interaction with virtual environments.

[0006] Minimally invasive surgeries are performed to minimize patient stress and also reduce hospital time and care, which can significantly reduce treatment costs. However, the correct generation of the perception of softness in minimally invasive surgical procedures remains a challenge, as - the sterilization of suitable equipment, - the quality of the generated haptic feedback, - the costs for additionally implemented components, and - Training procedures are not yet fully feasible. In the well-known da Vinci surgical system, for example, kinesthetic feedback was only implemented in the fifth generation, although this system has been in use for twenty years.

[0007] Due to cost and time efficiency, most minimally invasive surgeries are performed predominantly with laparoscopic instruments operated by a surgeon, in contrast to robot-assisted teleoperated surgeries (Da Vinci, Hugo RAS). Surgeons in minimally invasive surgery often face problems such as - limited freedom of movement at a small intervention point, and - the fact that the tissue cannot be directly felt with the hands due to the surgical instrument used. Interaction with tissues and organs via a long instrument significantly reduces haptic judgment regarding the force to be applied, as no haptic cues or only kinesthetic cues can be perceived. Therefore, the use of minimally invasive instruments in laparoscopic surgery can lead to various complications or diagnostic uncertainty with regard to the surgeon's performance and the success rate of the operation.

[0008] To improve surgeon performance, haptic feedback is not new. However, the perception of induced tissue deformation has largely been replaced by the application of vibrotactile feedback generated by electrodynamic actuators. However, this still does not allow the surgeon to intuitively distinguish between different tissues, providing only simple warning feedback. Given the very short penetration depth during tissue deformation by a grasper, even a kinesthetic feedback actuation mechanism such as the one used in the da Vinci system cannot provide surgeons with sufficient room to discriminate and assess tissue softness, even if it were highly transparent and robustly constructed.

[0009] For hard objects, i.e. objects into which the finger practically does not sink during haptic interaction, conclusions about the haptic texture are drawn primarily through kinesthetic cues. In contrast, humans perceive real soft objects, i.e. objects into which the finger sinks during haptic interaction, mainly through deformation and changes in the tactile surface on the skin, e.g. at the fingertip, when touched, which are resolved by the spatially distributed mechanoreceptor array on the skin. Therefore, these cues in particular must be presented during tool-based or virtual interaction with soft objects in order to correctly assess and differentiate the softness of objects such as tissue based on the deformation created. Although this information is known, there is no compact device that can display skin deformation and the skin tactile surface independently of one another.

[0010] The following devices and methods are known from the state of the art: 1. Non-compact stationary test benches for basic research [1]. However, these are not suitable for use in so-called haptic interfaces because they are too large and heavy. 2. Textile-based haptic interfaces for varying the skin contact area [2], [3]. With known textile-based actuators such as the F-WYD [2], [3], the deformation geometry and thus the skin contact area can be changed in a controlled manner. The deformable tactile surface is designed such that, during the full deformation to be represented, the lateral edges of the tactile finger are not touched over a large area. This prevents the simulation of particularly soft deformed surfaces (such as soft organ tissue, blackboard sponge). In addition, the textile tactile surface has its own compliance, which makes it impossible to represent harder objects. 3. A pneumatic mechanism for active haptic representation [4]. The proposed pneumatic mechanism is only suitable for active haptic exploration, i.e., the user actively presses the finger against the inflatable mechanism. It does not describe how to design a passive haptic interface in which the mechanism remains continuously connected to the finger and is controlled depending on the interaction of the virtual finger representation (e.g., laparoscopic instrument tip or finger of an avatar in a virtual environment) with the soft object. Due to its design, the tactile surface cannot be deformed in a controlled manner. Thus, the dynamic range is limited to small penetration depths. The inflatable mechanism for generating the finger deformation is mounted beneath the finger and cannot represent low compliance and thus harder objects, as it is itself deformable at the air pressures used. 4. Laparoscopic tools for displaying non-intuitive haptic information about compliance [5]. The described laparoscopic instrument can only display finger deformation, but not a variable skin contact surface, which, as already described, is essential for the perception of soft objects.

[0011] Therefore, none of the existing methods simultaneously offers a compact form factor, a highly dynamic haptic representation of compliance and an independent variation of pressure and skin contact area.

[0012] Based on the state of the art, the task was to provide a device that can passively haptically represent the compliance of objects, whereby the entire haptic range from very hard objects to very soft objects can be represented with the device.

[0013] The invention solves this problem by a device according to claim 1, a system according to claim 6 and a method according to claim 7. Detailed description

[0014] The invention provides a device for the passive haptic representation of the compliance of objects. The device comprises • a tactile surface; • a printing stamp; • a support structure; • a pressure actuator; and • a deformation actuator.

[0015] In the context of the invention, passive haptic representation of the compliance of an object means that the compliance of an object is represented to a human without the user directly touching the object with their hands and without the user actively moving it relative to the device according to the invention. The representation is achieved by the device according to the invention by imitating the feeling of touching the object.

[0016] For this purpose, the tactile surface of the device according to the invention has a non-deformable contact surface. Furthermore, the tactile surface has deformable contact surface edges laterally adjacent to the non-deformable contact surface. The deformable contact surface edges can, in particular, be bent.

[0017] In a preferred embodiment, the non-deformable contact surface of the touch surface is arranged centrally on the touch surface. According to the invention, the non-deformable contact surface serves as a finger support surface. According to the invention, a user positions their finger with the side belonging to the palm of the hand on the non-deformable contact surface. The non-deformable contact surface is inseparably connected to the support structure of the device.

[0018] To the side of the non-deformable contact surface, the tactile surface has deformable contact surface edges. Preferably, these are exactly two contact surface edges. When a finger is placed on the non-deformable contact surface, one deformable contact surface edge is located on the right side of the phalanx and one deformable contact surface edge is located on the left side of the phalanx.

[0019] According to the invention, the tactile surface is configured, controlled by the deformation actuator, to deform the deformable contact surface edges such that the tactile surface assumes a U-shape. In the valley of the U-shape, the tactile finger rests on the non-deformable contact surface, while the contact surface edges are deformable enough to encompass the sides of the finger. This enables the simulation of the deformation behavior of objects with high compliance. The deformation of the contact surface edges into the desired shape is achieved by having them locally differently distributed flexural rigidity. In particular, the flexural rigidity of the contact surface edges at their outer edges is higher than the flexural rigidity of the contact surface edges adjacent to the non-deformable contact surface. The increased flexural rigidity is generated by local geometric adjustments.In one embodiment, the increased flexural rigidity is achieved by a cross-section of the contact surface edges that increases toward the outer edge. In another embodiment, the increased flexural rigidity is achieved by a pleated structure of the contact surface edges.

[0020] The geometry of the resulting inhomogeneous and rigid tactile surface is also designed so that a force applied by the deformation actuator causes a curved deformation of the contact surface edges. In one embodiment, the deformation actuator has a linear drive, through which a vertical thrust acts from below on the contact surface edges, thus deforming them in a curved manner.

[0021] The deformation of the contact surface edges preferably occurs to the same extent for all contact surface edges. If the device has two contact surface edges, the uniform deformation of the contact surface edges allows a finger to be evenly enclosed from both sides, thus optimally simulating the feeling of sinking into a surface.

[0022] The tactile surface is dimensioned so that a finger can be placed centrally on the tactile surface. When the U-shape is fully formed, the outer edges of the U-shape touch the sides of the finger, creating the perception of the finger sinking in. This is particularly important when the compliance of highly compliant objects is to be represented. This function of the device according to the invention thus represents a skin tactile surface cue.

[0023] In one embodiment of the present invention, the tactile surface comprises or consists of polyurethane (TPU).

[0024] Furthermore, the pressure plunger is controlled by the pressure actuator and touches a finger located on the sensing surface from above, i.e., on the back of the finger. In one embodiment, the pressure actuator and the deformation actuator are implemented as separate components. In another embodiment, the pressure actuator and the deformation actuator are integrated into a single component.

[0025] Preferably, the tactile surface, in particular the non-deformable contact surface, and the pressure plunger form a clamping mechanism between which a finger can be positioned. When the pressure plunger is lowered onto the finger, a clamping mechanism is created between the pressure plunger and the non-deformable contact surface connected to the support structure, thereby causing a deformation of the skin. This allows, in particular, hard objects to be represented with a slight degree of flexibility. This function of the device according to the invention represents a skin deformation cue.

[0026] Compliance describes the ability of a body to deform elastically under the action of a force or moment. It can be determined as the reciprocal of stiffness.

[0027] Hard objects are characterized by the fact that when touched with a finger, the finger does not sink into the surface. Hard objects therefore exhibit low compliance. The perception of a hard surface occurs exclusively through a deformation of the skin on the underside of the finger in response to the cues represented by the mechanism. According to the invention, a hard object with low compliance is understood to be an object whose perception upon touch occurs exclusively through a deformation of the skin on the underside of the finger. Humans do not perceive any perceptible elastic deformation of the object upon touch.

[0028] Soft objects, on the other hand, are characterized by the fact that a finger sinks into the surface when touching it, causing the skin on the sides of the finger to come into contact with the object and perceive a stimulus. Soft objects therefore exhibit a high degree of compliance. According to the invention, a soft object with a high degree of compliance is defined as an object whose perception upon touch is perceived as a sinking into the object. For humans, a perceptible elastic deformation of the object occurs upon touch.

[0029] According to the invention, the pressure stamp and the tactile surface can be controlled independently of each other.

[0030] Furthermore, the degree of deformation of the deformable tactile surface is controllable. This allows for a seamless representation of hard and soft objects. The greater the compliance of an object, the more a finger would sink into it when touching it. This can be represented by a greater deformation of the deformable contact surface edges. The greater the deformation of the deformable contact surface edges, the larger the skin contact area of ​​the finger with the tactile surface and the stronger the perceived sensation of "sinking in."

[0031] The holding structure connects the pressure stamp to the sensing surface and is non-elastic. The pressure actuator and the deformation actuator are also attached to the holding structure. According to the invention, the non-deformable contact surface and the pressure actuator are connected to one another via the holding structure. In a preferred embodiment, the holding structure has a C-shape, with the pressure stamp being attached to the upper end of the C-shape and the non-deformable contact surface of the sensing surface being attached to the lower end of the C-shape. In one embodiment, the holding structure has a sensing surface base which is designed such that the non-deformable contact surface is attached to it, thereby creating a non-detachable connection between the holding structure and the sensing surface.Since the support structure is not elastic, the non-detachable connection between the touch surface and the support structure in this embodiment ensures that the touch surface cannot be deformed in this area. The non-deformable contact surface of the touch surface is formed by the interaction of the support structure and the touch surface.

[0032] In one embodiment of the present invention, the support structure comprises or consists of glycol-modified polyethylene terephthalate (PETG).

[0033] In one embodiment of the present invention, the tactile surface is designed in the form of a closed elastic band. The non-deformable contact surface and the deformable contact surface edges are located on the upper side of the band. The non-deformable contact surface is connected to the support structure and is therefore non-deformable. The band is designed such that the contact surface edges are deformed by the force applied by the deformation actuator.

[0034] In one embodiment, the sensing surface has the described shape of a closed elastic band and the deformation actuator comprises a linear motor which exerts a force on the deformable contact surface edges through guide rods.

[0035] In a further embodiment, the tactile surface has the described shape of a closed elastic band, and the flexural rigidity of the deformable contact surface edges is influenced by a fold structure at the contact surface edges. The flexural rigidity can be influenced by varying the number and size of the folds in the fold structure. In one embodiment, the fold structure has 1, 2, 3, 4, or 5 folds. The number of folds is limited by the structural space constraints. In principle, any geometric shape that can influence the flexural rigidity of the contact surface edges is possible instead of folds.

[0036] The device according to the invention thus advantageously combines the display of skin deformation cues and skin tactile surface cues.

[0037] In one embodiment of the present invention, the tactile surface, in particular the non-deformable contact surface, further comprises a mechanism configured to enable kinesthetic feedback and / or vibrotactile feedback.

[0038] In one embodiment, a vibration motor can be mounted beneath the non-deformable contact surface, allowing the vibrations to propagate through the device to the skin, where they generate vibrotactile cues. The device can also be connected to a force feedback system, such as a haptic single-point contact device, via the non-deformable contact surface using the support structure to generate controlled kinesthetic feedback at the finger.

[0039] This allows the present invention to implement not only skin deformation cues and skin tactile surface cues, but also kinesthetic cues and vibrotactile cues. Advantageously, this allows for the mapping of all relevant haptic cues.

[0040] In a further embodiment of the invention, the device further comprises a software interface. The software interface serves to provide an interface to a computing unit. The computing unit can, for example, take over the control of the device according to the invention and specify which haptic impressions are to be represented with the device according to the invention. This can be used, for example, if haptic impressions from a virtual reality, e.g. a computer game, are to be represented by the device according to the invention. In this case, the virtual environment determines the force that the virtual contact point applies to the virtual object and thus the deformation, i.e. the depth of sinking, that is produced. This force and depth of sinking is represented on the skin by the device according to the invention. This makes the experience of virtual reality significantly more realistic.

[0041] Furthermore, the invention comprises a system comprising a device according to the invention and • a laparoscopic tool or • a haptic interface device or • a surgical robot, wherein the device according to the invention is connected to the haptic interface device or the laparoscopic tool or the surgical robot in such a way that a haptic representation of the compliance of objects is possible.

[0042] The haptic interface device or the laparoscopic tool or the surgical robot preferably has a tactile sensor system with the aid of which the compliance of an object can be detected and this information can be transmitted to the device according to the invention. Force and displacement (i.e. sinking depth) at the tip of the tools on the object are preferably measured directly or indirectly using sensors and fed into a closed control loop which controls the actuators of the device. In a further embodiment, sensors are used which measure the geometry and compliance of a deformation. The control loop then controls the deformable contact surfaces of the tactile surface via the deformation actuator, which increase the contact of the tactile surface with the skin of the finger through deformation. This corresponds to the skin contact with the object which occurs during direct interaction, e.g.The finger would feel the object, allowing for an intuitive assessment of the object's haptic properties. This is implemented analogously via the pressure actuator and the pressure stamp.

[0043] If the compliance of objects from virtual reality is represented by the device according to the invention, the compliance of the objects is stored, for example, in a database or by models and a computing unit gives the corresponding control commands to the pressure actuator and the deformation actuator.

[0044] The device can thus be used in conjunction with laparoscopic tools, haptic interface devices or a surgical robot in order to enable the surgeon to haptically experience distant objects, particularly tissue, during operations or treatments, for example in robot-assisted surgery.

[0045] By "feeling" the tissue and its structure, the surgeon receives additional valuable information via the device or system according to the invention. Minimally invasive surgical instruments can be improved with the present invention so that a surgeon can better assess the deformability of tissue haptically and thus integrate intuitive haptic information into their workflow.

[0046] Furthermore, the invention further provides a method for passively haptically representing the compliance of objects with a device according to the invention, wherein • a finger is positioned with its underside on the non-deformable contact surface of the tactile surface, with the back of the finger facing the pressure stamp; and (a) pressure is exerted on the back of the finger by the pressure stamp or (b) pressure is exerted on the back of the finger by the pressure stamp and the deformable contact surface edges around the finger are deformed.

[0047] All features that have already been described for the device according to the invention apply to the same extent to the system according to the invention and the method according to the invention and vice versa.

[0048] Preferably, the pressure stamp and the sensing surface, in particular the deformable contact surface edges, are controlled independently of each other.

[0049] In one embodiment of the method according to the invention, information about the compliance of an object is measured by at least one tactile sensor, and this information is used to control the pressure actuator and the deformation actuator in a closed control loop.

[0050] In a further embodiment of the method according to the invention, information about the compliance of an object is available in a database and this information is used to control the pressure actuator and the deformation actuator in a closed control loop.

[0051] In one embodiment of the present invention, the method further comprises kinesthetic feedback and / or vibrotactile feedback. These feedbacks are generated beneath the non-deformable contact surface of the tactile surface.

[0052] Preferably, the method according to the invention exclusively depicts hard objects with low compliance through process step (a). For hard objects, imaging skin contact on the sides of the finger is not necessary, since the finger would not sink into a hard object with low compliance. In this case, only the pressure pad exerts pressure on the back of the finger, thus generating a skin deformation cue.

[0053] Furthermore, soft objects with a high degree of compliance are preferably represented by process step (b). In this case, the pressure stamp exerts pressure on the back of the finger, while the tactile surface is bent upwards into a U-shape around the finger. Due to the pressure on the back of the finger and the skin contact of the deformable contact surface edges of the tactile surface with the sides of the fingers, the finger perceives a sensation of sinking. Thus, a skin deformation cue and a skin tactile surface cue are generated simultaneously.

[0054] Any states can be represented between the extremes of the process steps a) and b).

[0055] In the following, the invention is explained in more detail with reference to 6 figures. Fig. 1 shows an embodiment of the device according to the invention; Fig. Figure 2 (A) shows an embodiment of the device according to the invention, (B) shows a deformation by a finger in an elastic reference surface; Fig. 3 (A) shows a system according to the invention and (B) an enlarged section of this system according to the invention; Fig. 4 (A) shows a further system according to the invention and (B) to (D) show sections of this system; Fig. 5 (A) to (C) illustrate a device according to the invention; Fig. 6 (A) and (B) represent part of a device according to the invention.

[0056] Fig. Figure 1 illustrates an embodiment of the device 500 according to the invention. It depicts the pressure plunger 20 and an index finger 30 positioned on the non-deformable contact surface 10b of the tactile surface 10 below the pressure plunger 20 in the device 500 according to the invention. The deformation of the deformable contact surface edges 10a of the tactile surface is clearly visible.

[0057] Fig. Figure 2 (A) illustrates an embodiment of the device 500 according to the invention. A finger 30 is located on the tactile surface 10. Above the back of the finger is the pressure plunger 20, which is controlled by the pressure actuator 40. The deformation actuator 50 acts on the deformable contact surface edges 10a of the tactile surface.

[0058] By bending upward the deformable contact surface edges 10a, skin contact is created on the sides of the finger, simulating the finger sinking into a soft surface. Between the flexible contact surface edges 10a, the tactile surface has a centrally arranged non-deformable contact surface 10b. The pressure stamp 20 and the tactile surface 10 are attached to the C-shaped support structure 80. Fig. 2 (B) illustrates the sinking of a finger 30 into an elastic reference surface 60. It can be clearly seen that the sinking leads to skin contact of the elastic surface with the sides of the finger 30.

[0059] Fig. 3 (A) illustrates a system according to the invention. The device 500 according to the invention is connected to a haptic interface device 70. Fig. 3 (B) shows an enlarged section of the Fig. 3 (A). A device 500 according to the invention with a finger 30 is shown. The finger 30 is located on the sensing surface 10 below the pressure plunger 20. The pressure plunger 20 and the deformation actuator 50 are attached to a support structure 80.

[0060] Fig. Figure 4 (A) illustrates another system 600 according to the invention, which includes the device 500 according to the invention and a laparoscopic tool. The system 600 according to the invention is used by a surgeon 130 who performs a minimally invasive operation on a patient 140 via an access in the abdominal cavity 120. The Fig. 4 (B) to (D) show enlarged sections of the Fig. 4 (A). In Fig. Figure 4 (B) shows the system 600 according to the invention with the device 500 according to the invention. The laparoscopic tool has a handle 90, a rod 100, and a tactile sensor 110 at the tool tip. Fig. 4 (C) and (D) show the device 500 according to the invention and the handle 90 in more detail.

[0061] Fig. 5 (A) to (C) illustrate an embodiment of the present invention in which the tactile surface 10 has the shape of a closed band. In this embodiment, the support structure 80 comprises a tactile surface base 12 to which the non-deformable contact surface 10b of the tactile surface 10 is attached. The connection between the support structure 80 and the tactile surface 10 forms a fixed support point for the finger 30 in the form of the non-deformable contact surface 10b. The tactile surface 10 extends around the guide rods 51 and 52 of the deformation actuator 50 and, in this example, has a pleated structure 11, 13 on the side. This pleated structure 11, 13 illustrated here has proven useful in empirical designs for realizing the desired curvature geometry of the deformable contact surface edges 10a. The deformation actuator 50 moves the guide rods 51, 52 upwards in a linear movement.The guide rods 51, 52 press the deformable contact surface edges 10a upwards.

[0062] In Fig. 5 (A), the deformation actuator 50 exerts no force on the sensing surface 10 and the deformable contact surface edges 10a are not deformed. Fig. 5(B) and (C), the deformation actuator 50 exerts a force and thereby pushes the deformable contact surface edges upward, causing them to bend laterally and horizontally toward the finger.

[0063] Fig. Figure 6 (A) illustrates part of a device according to the invention. The deformation actuator 50 here comprises two linear drives 54, two linear guides 53, and two push rods 55. The linear drives 54 move the push rods 55 upwards through the linear guide 53 and exert a force on the flexibly deformable contact surface edges 10a of the sensing surface 10. In this example, the sensing surface 10 has specially shaped curved thickenings at the deformable contact surface edges 10a. These thickenings enable a conversion of the linear pushing movement by the push rods 55 into an inward curvature of the contact surface edges 10a. While in Fig. 6 (A) no force acts on the touch surface 10, in Fig. 6 (B) The deformable contact surface edges 10a are bent upward and inward by the application of a force by the deformation actuator 50. The pressure stamp is not shown for clarity. Literatur [1] B. Li, S. C. Hauser, and G. J. Gerling, „Faster indentation influences skin deformation to reduce tactile discriminability of compliant objects,“ IEEE Transactions on Haptics, 2023. [2] M. Bianchi, E. Battaglia, M. Poggiani, S. Ciotti, and A. Bicchi, „A wearable fabricbased display for haptic multi-cue delivery,“ in 2016 IEEE haptics symposium (HAPTICS), 2016, pp. 277-283. [3] S. Fani, S. Ciotti, G. Pagnanelli, A. Moscatelli, Y. De Pra, and M. Bianchi, „Modulating the Perceived Softness of Real Objects Through Wearable Feel-Through Haptics,“ IEEE Transactions on Haptics, 2023. [4] M. Mete, H. Jeong, W. D. Wang, and J. Paik, „SORI: A softness-rendering interface to unravel the nature of softness perception,“ Proceedings of the National Academy of Sciences, vol. 121, no. 13, p. e2314901121, 2024. [5] DA Joseph, JA Hammerland, DE Kerr, and others, “Haptic touch feedback surgical device for palpating tissue,” 2022. List of reference symbols 10 Touch surface 10a deformable contact surface edges 10b non-deformable contact surface 11, 13 Fold structure 12 Touch surface base 20 printing stamps 30 fingers 40 pressure actuator 50 Deformation actuator 51, 52 Command staffs 53 Linear guide 54 Linear actuator 55 push rod 60 Comparison surface 70 haptic interface device 80 support structure 90 handle 100 bars 110 Touch sensors 120 Access to the abdominal cavity 130 Surgeon 140 patients 500 device 600 system

Claims

[1] Device (500) for the passive haptic representation of the compliance of objects comprising • a touch surface (10); • a printing stamp (20); • a support structure (80); • a pressure actuator (40); and • a deformation actuator (50); where the touch surface (10) has a non-deformable contact surface (10b) and has deformable contact surface edges (10a) laterally to the non-deformable contact surface (10b); the touch surface (10) is configured to deform the deformable contact surface edges (10a) under the control of the deformation actuator (50) such that the touch surface (10) assumes a U-shape; the pressure stamp (20) is controllable by the pressure actuator (40); Pressure stamp (20) and deformable contact surface edges (10a) are controllable independently of one another; and the non-deformable contact surface (10b) and the pressure actuator (40) are connected to one another via a common holding structure (80). [2] Device (500) according to claim 1, characterized by that the non-deformable contact surface (10b) of the tactile surface (10) further comprises a mechanism configured to enable kinesthetic feedback and / or vibrotactile feedback. [3] Device (500) according to one of the preceding claims, characterized by that the sensing surface (10) and the pressure stamp (20) form a clamping mechanism between which a finger (30) can be positioned. [4] Device (500) according to one of the preceding claims, characterized by that the tactile surface (10) has the shape of a closed band. [5] Device (500) according to one of the preceding claims, characterized by that the device further comprises a software interface. [6] System (600) comprising a device (500) according to one of claims 1 to 5 and a laparoscopic tool or a haptic interface device (70) or a surgical robot characterized by that the device according to one of claims 1 to 5 is connected to the haptic interface device or the laparoscopic tool or the surgical robot in such a way that a haptic representation of the compliance of objects is possible. [7] Method for passively haptically representing the compliance of objects with a device (500) according to one of claims 1 to 5, characterized by , that • a finger (30) is positioned with its underside on the non-deformable contact surface of the tactile surface (10), the back of the finger facing the pressure stamp (20); and (a) pressure is exerted on the back of the finger by the pressure stamp (20); or (b) pressure is exerted on the back of the finger by the pressure stamp (20) and the deformable contact surface edges (10a) of the tactile surface (10) deform around the finger (30). [8] Method according to claim 7, characterized by that the pressure stamp (20) and the deformable tactile surface edges (10a) are controlled independently of each other. [9] Method according to one of claims 7 to 8, characterized by that hard objects with low compliance are represented exclusively by process step (a). [10] Method according to one of claims 7 to 8, characterized by that soft objects with a high degree of compliance are represented by process step (b).

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