This paper micro Robot literature review is the second article about Micro Robot Control in laminar flow thesis. Here is the first one(https://tunavatansever.com/2021/05/09/micro-robot-control/). This time we are making literature review about micro robots. Have a nice readings…
1.2 Motivation
Cancer is one of the most common diseases which has been the cause of death in recent years. For many families, cancer loses its loved ones and leaves them in economically difficult situations. The methods used in the treatment of cancer are applied not to treat the patient but to slow the disease. In the chemotherapy process, the harmful rays applied to the patient harm other healthy tissues that the cancer does not reach. Even the most basic needs that can sustain the patient’s daily life cannot be done alone. This situation also negatively affects the relatives of patients.
The reason we start this project is to get a micro robot; that can be used in the treatment of diseases such as cancer. Thanks to this robot, the person can be treated with spot firing, and the person can be treated without exposure to harmful radiation as in chemotherapy. Thus, the healthy tissues of the person will be treated without any harm.
If this system is successfully implemented, we will be able to avoid purchasing existing systems and processes. Domestic production will be a treatment method. In this way, we will reduce the foreign exchange loss as a country.
1.3 Literature Review
Micro Robot literature review, in robotics, one generally compartmentalizes aspects of robot design such as kinematics, power, and control. It is unlikely that miniature devices that carry small, electric motors and batteries can be effectively scaled to submillimeter sizes. In the design of wireless microrobots, fabrication is fundamentally limited by scaling issues; and power and control are often inextricably linked. This forces us to take a different perspective on microrobot design than that found in traditional robotics.
The world of a medical microrobot consists of fluid-filled lumens (i.e., tubes) and cavities, as well as soft tissues. Medical microrobots must be designed specifically to work in these environments. But the relative changes in the size, geometry, and material properties of the environment within a given procedure present design challenges.
Fluid flow in the microrobot’s environment also presents a significant design challenge. Consider a microrobot designed to work in the circulatory system. In addition to dealing with varying blood vessel diameter, the microrobot must compete against the pulsating flow of blood; which is significant to a small, untethered device.
Although designing functional medical microrobots is challenging from an engineering perspective, the potential rewards are vast. Wireless microrobots are an alternative to catheter-based approaches, but they have fundamentally challenges engineering-design. Tethered devices cannot act as permanent or temporary implants, and their maneuverability is limited; once they reach the site of interest because some degrees of freedom (DOF) are no longer available for maneuverability.
Furthermore, micro robot literature review, many internal locations of the body are either inaccessible or hard to reach in a tethered fashion. In this review, we present the state of the art in medical microrobots and discuss potential applications for these devices that are realistic for the near future. We first discuss potential microrobot functions; as well as locations in the body where microrobots are likely to perform these functions. We then discuss the critical issue of wireless power and the methods of transducing that power into locomotion.
Finally, micro robot literature review, we discuss localization of in vivo microrobots, which will be required for both feedback control and safety concerns. We will not place emphasis on wireless micro electromechanical systems (MEMS) devices; which tend to be either sensor or actuator oriented and have no locomotion capabilities (e.g. implants). The circulatory system consists of the heart and the vessels used to carry blood around the body. Blood vessels consist mainly of four types of tissue: endothelium (internal wall lining), elastic tissue (for pulsation damping), smooth muscle, and connective tissue.
The relative composition of a given vessel depends on its function and distance from the heart. As the distance between the heart and a given blood vessel increases, the pressure pulsation resulting from the beating heart becomes attenuated, reaching a limiting behavior of constant flow in the capillaries.
Figure 1.1: Schematic representation of the vessels of the cardiovascular system, with the inner diameter, average blood-flow speed, and Reynolds number from Berger
Figure 1.1 shows the blood-flow velocity and Reynolds number as a function of vessel size.
The Reynolds number reported is that describing pipe flow. In addition to average values, the maximum flow velocities and Reynolds numbers are also critical, reaching Re = 8500 in the aorta and 1000 in the arteries (30). Blood consists largely of a watery fluid named plasma; in which red and white blood cells measuring 5–10 μm and smaller platelets are suspended. Although blood has many properties (density 1060 kg m−3, pH 7.38–7.42, surface tension 55– 61 × 10−3 Nm−1) that are approximately the same as water. Its apparent viscosity (3.5 × 10−3 Pa s) is three times higher, primarily owing to suspended red blood cells.
The reported properties of blood come from studies that treat it as a homogeneous fluid—an assumption that loses accuracy at the microscale. Depending on its size, a microrobot could very well experience a working environment closer to obstacle-filled plasma than “blood” as described by a homogeneous model.
Nearly every site of the body can be accessed by blood, so the circulatory system is arguably the most important application area for wireless microrobots. Some of the most promising applications for microrobots in the circulatory system include performing targeted drug delivery, removing plaque (rotational atherectomy), destroying blood clots (thrombolysis) acting as stents tomaintain blood flow, acting as occlusions to intentionally starve a region of nutrition, and administering therapy for aneurysms.
Micro robots could also carry electrodes for electrophysiology. The small-diameter capillary network makes unlikely the possibility of round-trip navigation of the body; with the microrobot always moving with the flow. Consequently, a viable microrobot is likely to require the ability to move against the flow. Martel and colleagues have configured a clinical magnetic resonance imaging (MRI) system to control the movement of a magnetic bead in the circulatory system; and have actually performed in vivo trials in the artery of a living swine. They find that generating enough force to move against blood flow is challenging but possible.
First article :
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