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 touch surface; • a pressure plunger; • a holding structure; • a pressure actuator; and • a deformation actuator, wherein the touch surface has a non-deformable contact surface and flexibly deformable contact surface edges laterally to the non-deformable contact surface. The touch surface is designed to deform the deformable contact surface edges, under control by the deformation actuator, in such a way that the touch surface assumes a U-shape. Furthermore, the pressure plunger can be controlled by the pressure actuator, and the pressure plunger and the deformable contact surface edges can be controlled independently of one another. The invention further relates to a system comprising the device according to the invention and to a method for the passive haptic representation of the compliance of objects.

Description

[0001] Device for the passive haptic representation of the compliance of objects

[0002] Description

[0003] The invention relates to a device for the passive haptic representation of the compliance of objects having

[0004] • a tactile surface;

[0005] • a printing stamp;

[0006] • a support structure;

[0007] • a pressure actuator; and

[0008] • a deformation actuator; wherein the sensing surface has a non-deformable contact surface and flexibly deformable contact surface edges laterally to the non-deformable contact surface. The sensing surface is configured to deform the deformable contact surface edges, controlled by the deformation actuator, such that the sensing surface assumes a II shape. Furthermore, the pressure stamp is controllable by the pressure actuator, and the pressure stamp and the deformable contact surface edges are controllable independently of each other. In addition, the invention comprises a system including the device according to the invention and a method for the passive haptic representation of the compliance of objects.

[0009] The haptic perception of the compliance of objects and their surfaces is an essential source of information for humans in many fields of application. When interacting with objects that are not reachable by hand, direct interaction is not possible, and therefore the compliance of these objects cannot be directly perceived via the sensory receptors of the hands and fingers. This can occur, for example, in telesurgery or laparoscopic surgery. In laparoscopic surgery, which is a minimally invasive method, rod-shaped surgical instruments are used.

[0010] Using instruments (laparoscope), a procedure is performed in the abdominal cavity. 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 directly touch it with their fingers. Therefore, haptic perception of the tissue's elasticity is not possible. Teleoperations are performed by remotely controlled robots. The surgical instruments are operated by a robotic arm, so that in this area, the same limitations regarding the haptic perception of objects (tissue) and elasticity arise as already described for laparoscopic operations.

[0011] Another area where direct haptic perception through the hands is not possible is the entire realm of virtual reality. The responsiveness of virtual objects, such as those displayed through VR headsets, cannot be perceived by a human. The experience of virtual reality would become significantly more realistic if supplemented by the haptic perception of the responsiveness of objects touched within the virtual environment.

[0012] The highly dynamic passive haptic representation of soft and hard objects and surfaces remains a significant challenge, which can currently only be partially implemented. There are four relevant cues derived from haptic stimuli that must be accurately reproduced:

[0013] (1) Kinesthetic cues (resistance upon object contact)

[0014] (2) Vibrotactile cues (vibration by collision),

[0015] (3) Skin deformation cues (deformation of the skin due to pressure) and

[0016] (4) Skin surface cues (sinking of body parts such as a finger into a soft object or surface, thereby increasing the effective contact area between the object and the finger).

[0017] Currently, only acceptable technical solutions exist for displaying kinesthetic cues, vibrotactile cues, and skin deformation cues. A simple, technically practical representation of the variable skin contact area across a large compliance range, which can be combined with the aforementioned cues, does not yet exist. However, this would be particularly necessary in the fields of telerobotics, minimally invasive surgery or telesurgery, and interaction with virtual environments. TUD157WO Page 3

[0018] Minimally invasive procedures are performed to minimize patient stress and also reduce hospital time and care, thus significantly lowering treatment costs. However, correctly generating the perception of softness during minimally invasive surgical procedures remains a challenge, as

[0019] - the sterilization of suitable equipment,

[0020] - the quality of the generated haptic feedback,

[0021] - the costs for additionally implemented components, and

[0022] - Training methods as a whole are not yet fully feasible. For example, in the well-known da Vinci surgical system, kinesthetic feedback was only implemented in the fifth generation, even though this system has been in use for twenty years.

[0023] Most minimally invasive surgeries, due to cost and time efficiency, are predominantly performed with laparoscopic instruments operated by a surgeon, unlike robot-assisted telesurgical procedures (Da Vinci, Hugo RAS). Surgeons in minimally invasive surgery frequently encounter problems such as...

[0024] - limited freedom of movement at a small point of intervention, and

[0025] - the fact that the tissue cannot be directly palpated by hand due to the surgical instrument used. Interacting with tissues and organs via a long instrument significantly reduces haptic judgment regarding the force to be applied, as no haptic cues are perceived, or only kinesthetic ones. Therefore, the use of minimally invasive instruments in laparoscopic surgery can lead to various complications and diagnostic uncertainty regarding the surgeon's performance and the success rate of the operation.

[0026] To enhance surgeons' performance, the implementation of haptic feedback in minimally invasive instruments is not a new concept. However, the perception of tissue deformation has largely been replaced by vibrotactile feedback generated by electrodynamic actuators. This still does not allow surgeons to intuitively distinguish between different tissues, but only provides a simple warning. Given the very shallow penetration depth during tissue deformation by a grasper, even a kinesthetic feedback actuation mechanism, such as that used in the da Vinci system, cannot provide surgeons with sufficient space to differentiate tissues and assess tissue softness, even if it were highly transparent and robustly constructed.

[0027] For hard objects—that is, objects into which the finger barely sinks during haptic interaction—inferences about their haptic properties are made primarily through kinesthetic cues. In contrast, humans perceive real soft objects—that is, objects into which the finger sinks during haptic interaction—mainly through deformation and changes in the tactile surface of the skin, for example, at the fingertip, upon touch. These changes are resolved by the spatially distributed array of mechanoreceptors on the skin. Therefore, these cues, in particular, must be represented 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 generated deformation. Although this information is known, there is no compact device that can represent skin deformation and skin tactile surface independently.

[0028] The following devices and methods are known from the prior art:

[0029] 1. Non-compact stationary test stands for basic research

[0001] , However, these are not suitable for use in so-called haptic interfaces because they are too large and too heavy.

[0030] 2. Textile-based haptic interfaces for varying the skin contact area [2], [3]. In known textile-based actuators such as the F-WYD [2], [3], the deformation geometry and thus the skin contact area can be controlled and changed. The deformable tactile surface is designed so that, during the full deformation to be represented, the lateral edges of the tactile finger are not in contact over a large area. This prevents the simulation of particularly soft deformed surfaces (such as soft organ tissue or chalkboard eraser). Furthermore, the textile tactile surface has its own inherent compliance, which makes it impossible to simulate harder objects.

[0031] 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 their 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 TUD157WO page 5 or finger of an avatar in a virtual environment) with the soft object. Due to the principle, the tactile surface cannot be deformed in a controlled manner. Therefore, the dynamic range is limited to small compression depths.The inflatable mechanism for generating finger deformation is located below the finger and cannot represent low compliance and therefore harder objects, as it is itself deformable at the air pressures used.

[0032] 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.

[0033] None of the existing methods therefore offers simultaneously a compact form factor, a highly dynamic haptic representation of compliance and an independent variation of pressure and skin contact area.

[0034] 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.

[0035] The invention solves this problem by means of a device according to claim 1, a system according to claim 6 and a method according to claim 7.

[0036] Detailed description

[0037] The invention provides a device for the passive haptic representation of the compliance of objects. The device features

[0038] • a tactile surface;

[0039] • a printing stamp;

[0040] • a support structure;

[0041] • a pressure actuator; and

[0042] • a deformation actuator.

[0043] Passive haptic representation of the compliance of an object, in the context of the invention, means that the compliance of an object is represented to a person without the user directly touching the object with their hands (TUD157WO, page 6) and without the user performing any active movement relative to the device according to the invention. The representation is achieved by the device according to the invention by imitating the sensation of touching the object.

[0044] 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 to the non-deformable contact surface. The deformable contact surface edges can, in particular, be bent.

[0045] In a preferred embodiment, the non-deformable contact surface of the tactile surface is arranged centrally on the tactile surface. According to the invention, the non-deformable contact surface serves as a finger resting surface. A user positions their finger with the palm-side facing the non-deformable contact surface. The non-deformable contact surface is permanently connected to the device's holding structure.

[0046] The tactile surface has deformable contact surface edges adjacent to the non-deformable contact surface. Preferably, there are exactly two contact surface edges. If a finger is positioned on the non-deformable contact surface, one deformable contact surface edge is located on the right side of the finger joint and one on the left side.

[0047] 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 an ll-shape. In the valley of the ll-shape, the sensing finger rests on the non-deformable contact surface, while the contact surface edges are deformable enough to completely encircle the sides of the finger. This enables the deformation behavior of highly compliant objects to be replicated. The deformation of the contact surface edges into the desired shape is achieved by their locally distributed bending stiffness. In particular, the bending stiffness of the contact surface edges at their outer edges is higher than the bending stiffness of the contact surface edges adjacent to the non-deformable contact surface. The increased bending stiffness is generated by local geometric adjustments.In one embodiment, the increased bending stiffness is achieved by a cross-section of the contact surface edges that increases towards the outer edge. In another embodiment, the increased bending stiffness is achieved by a folded structure of the contact surface edges. TUD157WO Page 7.

[0048] The geometry of the resulting inhomogeneously rigid sensing surface is designed such that a force applied by the deformation actuator causes a curving deformation of the contact surface edges. In one embodiment, the deformation actuator has a linear drive that applies a vertical thrust from below to the contact surface edges, thereby curving them.

[0049] 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 sensation of sinking into a surface.

[0050] The tactile surface is dimensioned such that a finger can be placed centrally on it. Once the U-shape is fully formed, the outer edges of the U-shape touch the sides of the finger, creating the sensation of the finger sinking in. This is particularly important when the compliance of highly compliant objects needs to be demonstrated. This function of the device according to the invention thus replicates a skin-touch surface cue.

[0051] In one embodiment of the present invention, the tactile surface has or consists of polyurethane (TPU).

[0052] Furthermore, the pressure stamp is controllable by the pressure actuator and touches a finger located on the touch surface from above, i.e., on the back of the finger. In one embodiment, the pressure actuator and the deformation actuator are implemented in separate components. In another embodiment, the pressure actuator and the deformation actuator are integrated into a single component.

[0053] Preferably, the tactile surface, in particular the non-deformable contact surface, and the pressure stamp form a clamping mechanism between which a finger can be positioned. When the pressure stamp is lowered onto the finger, a clamping mechanism is created between the pressure stamp and the non-deformable contact surface connected to the holding structure, thereby deforming the skin. This allows, in particular, the representation of hard objects with low compliance. This function of the device according to the invention constitutes a skin deformation cue. TUD157WO Page 8

[0054] Compliance describes the property of a body to deform elastically under the influence of a force or moment. It can be determined as the reciprocal of stiffness.

[0055] Hard objects are characterized by the fact that when touched with a finger, the finger does not sink into the surface. Hard objects thus exhibit low compliance. The perception of a hard surface occurs solely through a deformation of the skin on the underside of the finger within the range of cues achievable by the mechanism. According to the invention, a hard object with low compliance is understood to be an object whose perception upon touch occurs solely through a deformation of the skin on the underside of the finger. No perceptible elastic deformation of the object occurs for the human being upon contact.

[0056] Soft objects, on the other hand, are characterized by the fact that a finger sinks into the surface when touched, thus also bringing the skin on the sides of the finger into contact with the object and perceiving a sensation. Soft objects therefore exhibit a high degree of compliance. According to the invention, a soft object with high compliance is understood to be an object whose sensation of sinking into the object is perceived upon touch. For the human being, a perceptible elastic deformation of the object occurs upon contact.

[0057] According to the invention, the printing stamp and the touch surface can be controlled independently of each other.

[0058] Furthermore, the degree of deformation of the deformable tactile surface is controllable. This allows for a stepless representation between hard and soft objects. The greater the compliance of an object, the more a finger would sink into it upon contact. 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 sensation of "sinking in" is perceived.

[0059] The retaining 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 retaining structure. According to the invention, the non-deformable contact surface and the TUD157WO page 9

[0060] The pressure actuator and the stylus surface are connected via the mounting structure. In a preferred embodiment, the mounting structure has a C-shape, with the pressure plunger attached to the upper end of the C-shape and the non-deformable contact surface of the stylus surface at the lower end. In another embodiment, the mounting structure has a stylus surface base designed such that the non-deformable contact surface is attached to it, thereby creating a permanent connection between the mounting structure and the stylus surface. Since the mounting structure is not elastic, the permanent connection between the stylus surface and the mounting structure in this embodiment prevents the stylus surface from being deformed in this area. The non-deformable contact surface of the stylus surface is formed by the interaction of the mounting structure and the stylus surface.

[0061] In one embodiment of the present invention, the holding structure comprises or consists of glycol-modified polyethylene terephthalate (PETG).

[0062] In one embodiment of the present invention, the sensing 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 holding structure and is therefore not deformable. The band is designed such that the contact surface edges are deformed by a force applied by the deformation actuator.

[0063] In one embodiment, the tactile surface has the described shape of a closed elastic band, and the deformation actuator has a linear motor that exerts a force on the deformable contact surface edges via guide rods.

[0064] In another embodiment, the stylus surface has the described shape of a closed elastic band, and the bending stiffness of the deformable contact surface edges is influenced by a fold structure at these edges. The bending stiffness can be influenced by varying the number and size of the folds in this structure. In one embodiment, the fold structure has 1, 2, 3, 4, or 5 folds. The number of folds is limited by the available installation space. In principle, any geometric shape that can influence the bending stiffness of the contact surface edges is possible instead of folds. TUD157WO Page 10

[0065] The device according to the invention thus advantageously combines the display of skin deformation cues and skin touch surface cues.

[0066] In one embodiment of the present invention, the tactile surface, in particular the non-deformable contact surface, further comprises a mechanism designed to enable kinesthetic feedback and / or vibrotactile feedback.

[0067] In one embodiment, a vibration motor can be mounted beneath the non-deformable contact surface, allowing vibrations to propagate through the device to the skin and generate vibrotactile cues. The device can also be connected via the non-deformable contact surface and the mounting structure to a force feedback system, such as haptic single-point contact devices, to generate controlled kinesthetic feedback at the finger.

[0068] This means that not only skin deformation cues and skin tactile surface cues, but also kinesthetic and vibrotactile cues can be implemented using the present invention. Advantageously, this allows for the representation of all relevant haptic cues.

[0069] In a further embodiment of the invention, the device also features a software interface. This interface serves to provide a connection to a computing unit. The computing unit can, for example, control the device according to the invention and specify which haptic sensations are to be displayed. This can be used, for instance, when the device according to the invention is to display haptic sensations from a virtual reality, such as a computer game. In this case, the virtual environment determines the force exerted by the virtual contact point on the virtual object, and thus the resulting deformation, i.e., the depth of penetration. This force and depth of penetration are then displayed on the skin by the device according to the invention. This makes the experience of a virtual reality significantly more realistic.

[0070] Furthermore, the invention comprises a system comprising a device according to the invention and

[0071] • a laparoscopic instrument or

[0072] • a haptic interface device or TUD157WO page 11 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.

[0073] Preferably, the haptic interface device, laparoscopic tool, or surgical robot has tactile sensors that can detect the compliance of an object and transmit this information to the device according to the invention. Preferably, force and displacement (i.e., penetration depth) at the tip of the tool are measured directly or indirectly on the object by means of sensors and fed into a closed control loop that controls the actuators of the device. In a further embodiment, sensors are used that 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, through deformation, increases the contact of the tactile surface with the skin of the finger. This corresponds to the skin contact with the object that occurs during direct interaction, e.g.,The object's texture would be perceptible to the finger, allowing for an intuitive assessment of its haptic properties. This is implemented analogously via the pressure actuator and the pressure stamp.

[0074] 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 sends the corresponding control commands to the pressure actuator and the deformation actuator.

[0075] The device can thus be used in conjunction with laparoscopic tools, haptic interface devices or a surgical robot to make objects, especially tissues, that are remote to the surgeon haptically perceptible during operations or treatments, e.g. in robot-assisted surgery.

[0076] By "feeling" the tissue and its structure via the device or system according to the invention, the surgeon receives additional valuable information (TUD157WO page 12). Minimally invasive surgical instruments can be improved with the present invention in such a way that a surgeon can better assess the deformability of tissue haptically and thus integrate intuitive haptic information into his workflow.

[0077] Furthermore, the invention provides a method for passively haptically representing the compliance of objects with a device according to the invention, wherein

[0078] • 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 stamp; and

[0079] (a) pressure is exerted on the back of the finger by the pressure stamp or

[0080] (b) pressure is exerted on the back of the finger by the pressure stamp and the deformable contact surface edges around the finger deform.

[0081] All features already described for the device according to the invention apply equally to the system and method according to the invention and vice versa.

[0082] Preferably, the pressure stamp and the stylus surface, in particular the deformable contact surface edges, are controlled independently of each other.

[0083] In one embodiment of the method according to the invention, information about the compliance of an object is measured by at least one touch sensor and the pressure actuator and the deformation actuator are controlled by this information in a closed control loop.

[0084] In a further embodiment of the method according to the invention, information about the compliance of an object is stored in a database and the pressure actuator and the deformation actuator are controlled by this information in a closed control loop.

[0085] In one embodiment of the present invention, the method further comprises kinesthetic feedback and / or vibrotactile feedback. This feedback is generated beneath the non-deformable contact surface of the stylus. TUD157WO Page 13

[0086] Preferably, the inventive method is used to represent hard objects with low compliance solely through process step (a). With hard objects, it is not necessary to create skin contact on the sides of the finger, since the finger would not sink into a hard object with low compliance. In this case, only the pressure stamp exerts pressure on the back of the finger, thereby generating a skin deformation cue.

[0087] Furthermore, soft objects with high 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 around the finger into a II shape. 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 finger, the finger perceives a sensation of sinking. Thus, a skin deformation cue and a skin tactile surface cue are generated simultaneously.

[0088] Any states can be represented between the extrema of the process steps a) and b).

[0089] The invention is explained in more detail below with reference to 6 figures.

[0090] Figure 1 shows an embodiment of the device according to the invention;

[0091] Figure 2 (A) shows an embodiment of the device according to the invention, (B) shows a deformation by a finger in an elastic comparison surface;

[0092] Figure 3 (A) shows a system according to the invention and (B) an enlarged version.

[0093] Excerpt of this system according to the invention;

[0094] Figure 4 (A) represents another system according to the invention and (B) to (D) represent

[0095] Excerpts of this system are shown;

[0096] Figures 5 (A) to (C) represent a device according to the invention;

[0097] Figure 6 (A) and (B) represent part of a device according to the invention.

[0098] Figure 1 shows an embodiment of the device 500 according to the invention. The figure depicts the pressure stamp 20 and an index finger 30, which is positioned on the non-deformable contact surface 10b of the stylus surface 10 below the pressure stamp 20 in the device 500 according to the invention. The deformation of the deformable contact surface edges 10a of the stylus surface is clearly visible. TUD157WO Page 14

[0099] Figure 2 (A) shows 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 stamp 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.

[0100] By bending upwards the deformable contact surface edges 10a, skin contact is created on the sides of the finger, which imitates 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 retaining structure 80. Figure 2 (B) shows the sinking of a finger 30 into an elastic reference surface 60. It is clearly visible that the sinking results in skin contact between the elastic surface and the sides of the finger 30.

[0101] Figure 3(A) depicts a system according to the invention. The device 500 according to the invention is connected to a haptic interface device 70. Figure 3(B) shows an enlarged section of Figure 3(A). It depicts a device 500 according to the invention with a finger 30. The finger 30 is located on the tactile surface 10 below the pressure stamp 20. The pressure stamp 20 and the deformation actuator 50 are attached to a holding structure 80.

[0102] Figure 4(A) shows another system 600 according to the invention, which comprises the device 500 according to the invention and a laparoscopic instrument. 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 point in the abdominal cavity 120. Figures 4(B) to (D) show enlarged sections of Figure 4(A). In Figure 4(B), the system 600 according to the invention is shown with the device 500 according to the invention. The laparoscopic instrument has a handle 90, a rod 100, and a tactile sensor 110 at the instrument tip. Figures 4(C) and (D) show the device 500 according to the invention and the handle 90 in more detail.

[0103] Figures 5(A) to (C) illustrate an embodiment of the present invention in which the sensing surface 10 has the form of a closed band. In this embodiment, the holding structure 80 has a sensing surface base 12 to which the non-deformable contact surface 10b of the sensing surface 10 is attached. The connection between TUD157WO page 15

[0104] The holding structure 80 and the tactile surface 10 form a fixed contact 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 folded structure 11, 13 on its side. This folded structure 11, 13, as shown 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 motion. During this movement, the guide rods 51, 52 push the deformable contact surface edges 10a upwards.

[0105] In Figure 5(A), the deformation actuator 50 exerts no force on the stylus surface 10, and the deformable contact surface edges 10a are not deformed. In Figures 5(B) and (C), the deformation actuator 50 exerts a force, thereby pushing the deformable contact surface edges upwards, causing them to curve laterally and horizontally towards the finger.

[0106] Figure 6(A) shows part of a device according to the invention. The deformation actuator 50 has 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 guides 53, exerting 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 the linear push motion by the push rods 55 to be converted into an inward curvature of the contact surface edges 10a. While no force acts on the sensing surface 10 in Figure 6(A), in Figure 6(B) the deformable contact surface edges 10a are bent upwards and inwards by the force exerted by the deformation actuator 50. The printing stamp is not shown for better illustration.

[0107] TUD157WO Seite 16

[0108] Literatur

[0109] [1] B. Li, S. C. Hauser, and G. J. Gerling, Taster indentation influences skin deformation to reduce tactile discriminability of compliant objects," IEEE Transactions on Haptics, 2023.

[0110] [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.

[0111] [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.

[0112] [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.

[0113] [5] DA Joseph, JA Hammerland, DE Kerr, and others, “Haptic touch feedback surgical device for palpating tissue,” 2022.

[0114] TUD157WO Page 17

[0115] Reference symbol list

[0116] 10 Touch surface

[0117] 10a deformable contact surface edges

[0118] 10b non-deformable contact surface

[0119] 11, 13 Fold structure

[0120] 12 tactile surface feet

[0121] 20 printing stamps

[0122] 30 fingers

[0123] 40 Print actuator

[0124] 50 Deformation actuator

[0125] 51, 52 Command staffs

[0126] 53 Linear guide

[0127] 54 Linear drive

[0128] 55 Push rod

[0129] 60 comparison surfaces

[0130] 70 haptic interface device

[0131] 80 Support structure

[0132] 90 Handle

[0133] 100 rods

[0134] 110 Touch sensors

[0135] 120 Access to the abdominal cavity

[0136] 130 Surgeon

[0137] 140 patients

[0138] 500 Device

[0139] 600 System

Claims

TUD157WO Page 18 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); wherein the sensing surface (10) has a non-deformable contact surface (10b) and deformable contact surface edges (10a) laterally to the non-deformable contact surface (10b); the sensing surface (10) is configured to deform the deformable contact surface edges (10a) controlled by the deformation actuator (50) such that the sensing surface (10) assumes an ll-shape; the pressure stamp (20) is controllable by the pressure actuator (40); The printing stamp (20) and deformable contact surface edges (10a) are independently controllable; and the non-deformable contact surface (10b) and the printing actuator (40) are connected to each other via a common holding structure (80).

2. Device (500) according to claim 1 , characterized in that the non-deformable contact surface (10b) of the tactile surface (10) further comprises a mechanism which is configured to enable kinesthetic feedback and / or vibrotactile feedback.

3. Device (500) according to one of the preceding claims, characterized in that the tactile 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 in that the sensing surface (10) has the form of a closed band.

5. Device (500) according to one of the preceding claims, characterized in that the device further comprises a software interface. TUD157WO Page 19 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 in 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 in that • a finger (30) is positioned with its underside on the non-deformable contact surface of the tactile surface (10), with the back of the finger facing the pressure stamp (20); and (a) pressure is applied to 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 in that the printing 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 in that hard objects with low compliance are produced exclusively by method step (a).

10. Method according to one of claims 7 to 8, characterized in that soft objects with high compliance are produced by method step (b).

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